javadoc(1)javadoc(1)NAMEjavadoc - The Java API Documentation Generator
Generates HTML pages of API documentation from Java source files.
This document contains Javadoc examples for Sun Solaris.
SYNOPSISjavadoc [ options ] [ packagenames ] [ sourcefilenames ] [ -subpack‐
ages pkg1:pkg2:... ] [ @argfiles ]
Arguments can be in any order. See processing of Source Files for
details on how the Javadoc tool determines which ".java" files to
process.
options
Command-line options, as specified in this document. To see a
typical use of javadoc options, see Real-World Example.
packagenames
A series of names of packages, separated by spaces, such as
java.lang java.lang.reflect java.awt. You must separately
specify each package you want to document. Wildcards are not
allowed; use -subpackages for recursion. The Javadoc tool uses
-sourcepath to look for these package names. See Example -
Documenting One or More Packages
sourcefilenames
A series of source file names, separated by spaces, each of
which can begin with a path and contain a wildcard such as
asterisk (*). The Javadoc tool will process every file whose
name ends with ".java", and whose name, when stripped of that
suffix, is actually a legal class name (see Identifiers @
http://java.sun.com/docs/books/jls/second_edition/html/lexi‐
cal.doc.html#40625). Therefore, you can name files with dashes
(such as X-Buffer), or other illegal characters, to prevent
them from being documented. This is useful for test files and
template files The path that precedes the source file name
determines where javadoc will look for the file. (The Javadoc
tool does not use -sourcepath to look for these source file
names.) Relative paths are relative to the current directory,
so passing in Button.java is identical to ./Button.java. A
source file name with an absolute path and a wildcard, for
example, is /home/src/java/awt/Graphics*.java. See Exam‐
ple - Documenting One or More Classes. You can also mix packa‐
genames and sourcefilenames, as in Example - Documenting Both
Packages and Classes
-subpackages pkg1:pkg2:...
Generates documentation from source files in the specified
packages and recursively in their subpackages. An alternative
to supplying packagenames or sourcefilenames.
@argfiles
One or more files that contain a list of Javadoc options,
packagenames and sourcefilenames in any order. Wildcards (*)
and -J options are not allowed in these files.
DESCRIPTION
The Javadoc tool parses the declarations and documentation comments in
a set of Java source files and produces a corresponding set of HTML
pages describing (by default) the public and protected classes, nested
classes (but not anonymous inner classes), interfaces, constructors,
methods, and fields. You can use it to generate the API (Application
Programming Interface) documentation or the implementation documenta‐
tion for a set of source files.
You can run the Javadoc tool on entire packages, individual source
files, or both. When documenting entire packages, you can either use
-subpackages for traversing recursively down from a top-level direc‐
tory, or pass in an explicit list of package names. When documenting
individual source files, you pass in a list of source (.java) file‐
names. Examples are given at the end of this document. How Javadoc pro‐
cesses source files is covered next.
Processing of source files
The Javadoc tool processes files that end in ".java" plus other files
described under Source Files. If you run the Javadoc tool by explicitly
passing in individual source filenames, you can determine exactly which
".java" files are processed. However, that is not how most developers
want to work, as it is simpler to pass in package names. The Javadoc
tool can be run three ways without explicitly specifying the source
filenames. You can (1) pass in package names, (2) use -subpackages, and
(3) use wildcards with source filenames (*.java). In these cases, the
Javadoc tool processes a ".java" file only if it fulfills all of the
following requirements:
o Its name, after stripping off the ".java" suffix, is actually a
legal class name (see Identifiers @
http://java.sun.com/docs/books/jls/second_edition/html/lexi‐
cal.doc.html#40625 for legal characters)
o Its directory path relative to the root of the source tree is
actually a legal package name (after converting its separators to
dots)
o Its package statement contains the legal package name (specified
in the previous bullet)
Processing of links - During a run, the Javadoc tool automatically adds
cross-reference links to package, class and member names that are being
documented as part of that run. Links appear in several places:
o Declarations (return types, argument types, field types)
o "See Also" sections generated from @see tags
o In-line text generated from {@link} tags
o Exception names generated from @throws tags
o "Specified by" links to members in interfaces and "Overrides"
links to members in classes
o Summary tables listing packages, classes and members
o Package and class inheritance trees
o The index
You can add hyperlinks to existing text for classes not included on the
command line (but generated separately) by way of the -link and
-linkoffline options.
Other processing details - The Javadoc tool produces one complete docu‐
ment each time it is run; it cannot do incremental builds -- that is,
it cannot modify or directly incorporate results from previous runs of
the Javadoc tool. However, it can link to results from other runs, as
just mentioned.
As implemented, the Javadoc tool requires and relies on the java com‐
piler to do its job. The Javadoc tool calls part of javac to compile
the declarations, ignoring the member implementation. It builds a rich
internal representation of the classes, including the class hierarchy,
and "use" relationships, then generates the HTML from that. The Javadoc
tool also picks up user-supplied documentation from documentation com‐
ments in the source code.
In fact, the Javadoc tool will run on .java source files that are pure
stub files with no method bodies. This means you can write documenta‐
tion comments and run the Javadoc tool in the earliest stages of design
while creating the API, before writing the implementation.
Relying on the compiler ensures that the HTML output corresponds
exactly with the actual implementation, which may rely on implicit,
rather than explicit, source code. For example, the Javadoc tool docu‐
ments default constructors @
http://java.sun.com/docs/books/jls/second_edi‐
tion/html/names.doc.html#36154 (section 8.6.7 of Java Language Specifi‐
cation) that are present in the .class files but not in the source
code.
In many cases, the Javadoc tool allows you to generate documentation
for source files whose code is incomplete or erroneous. This is a bene‐
fit that enables you to generate documentation before all debugging and
troubleshooting is done. For example, according to the Java Language
Specification, a class that contains an abstract method should itself
be declared abstract. The Javadoc tool does not check for this, and
would proceed without a warning, whereas the javac compiler stops on
this error. The Javadoc tool does do some primitive checking of doc
comments. Use the DocCheck doclet to check the doc comments more thor‐
oughly.
When the Javadoc tool builds its internal structure for the documenta‐
tion, it loads all referenced classes. Because of this, the Javadoc
tool must be able to find all referenced classes, whether bootstrap
classes, extensions, or user classes. For more about this, see How
Classes Are Found. Generally speaking, classes you create must either
be loaded as an extension or in the Javadoc tool's class path.
Javadoc Doclets
You can customize the content and format of the Javadoc tool's output
by using doclets. The Javadoc tool has a default "built-in" doclet,
called the standard doclet, that generates HTML-formatted API documen‐
tation. You can modify or subclass the standard doclet, or write your
own doclet to generate HTML, XML, MIF, RTF or whatever output format
you'd like. Information about doclets and their use is at the following
locations:
o Javadoc Doclets
o The -doclet command-line option
When a custom doclet is not specified with the -doclet command line
option, the Javadoc tool will use the default standard doclet. The
javadoc tool has several command line options that are available
regardless of which doclet is being used. The standard doclet adds a
supplementary set of command line options. Both sets of options are
described below in the options section.
Related Documentation and Doclets
o Javadoc Enhancements for details about improvements added in
Javadoc.
o Javadoc FAQ @
http://java.sun.com/j2se/javadoc/faq/index.html for answers to
common questions, information about Javadoc-related tools, and
workarounds for bugs.
o How to Write Doc Comments for Javadoc @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html for
more information about Sun conventions for writing documentation
comments.
o Requirements for Writing API Specifications @
http://java.sun.com/j2se/javadoc/writingapispecs/index.html -
Standard requirements used when writing the Java 2 Platform Speci‐
fication. It can be useful whether you are writing API specifica‐
tions in source file documentation comments or in other formats.
It covers requirements for packages, classes, interfaces, fields
and methods to satisfy testable assertions.
o Documentation Comment Specification @
http://java.sun.com/docs/books/jls/first_edition/html/18.doc.html
- The original specification on documentation comments, Chapter
18, Documentation Comments, in the Java Language Specification,
First Edition, by James Gosling, Bill Joy, and Guy Steele. (This
chapter was removed from the second edition.)
o DocCheck Doclet @
http://java.sun.com/javadoc/doccheck - Checks doc comments in
source files and generates a report listing the errors and irregu‐
larities it finds. It is part of the Sun Doc Check Utilities.
o MIF Doclet @
http://java.sun.com/javadoc/mifdoclet - Can automate the genera‐
tion of API documentation in MIF, FrameMaker and PDF formats. MIF
is Adobe FrameMaker's interchange format.
Terminology
The terms documentation comment, doc comment, main description, tag,
block tag, and in-line tag are described at Documentation Comments.
These other terms have specific meanings within the context of the
Javadoc tool:
generated document
The document generated by the javadoc tool from the doc comments
in Java source code. The default generated document is in HTML
and is created by the standard doclet.
name
A name of a program element written in the Java Language -- that
is, the name of a package, class, interface, field, constructor
or method. A name can be fully-qualified, such as
java.lang.String.equals(java.lang.Object), or partially-quali‐
fied, such as equals(Object).
documented classes
The classes and interfaces for which detailed documentation is
generated during a javadoc run. To be documented, the source
files must be available, their source filenames or package names
must be passed into the javadoc command, and they must not be
filtered out by their access modifier (public, protected, pack‐
age-private or private). We also refer to these as the classes
included in the javadoc output, or the included classes.
included classes
Classes and interfaces whose details are documented during a run
of the Javadoc tool. Same as documented classes.
excluded classes
Classes and interfaces whose details are not documented during a
run of the Javadoc tool.
referenced classes
The classes and interfaces that are explicitly referred to in the
definition (implementation) or doc comments of the documented
classes and interfaces. Examples of references include return
type, parameter type, cast type, extended class, implemented
interface, imported classes, classes used in method bodies, @see,
{@link}, {@linkplain}, and {@inheritDoc} tags. (Notice this defi‐
nition has changed since 1.3 @
http://java.sun.com/j2se/1.3/docs/tooldocs/solaris/javadoc.html#ref‐
erencedclasses.) When the Javadoc tool is run, it should load
into memory all of the referenced classes in javadoc's bootclass‐
path and classpath. (The Javadoc tool prints a "Class not found"
warning for referenced classes not found.) The Javadoc tool can
derive enough information from the .class files to determine
their existence and the fully-qualified names of their members.
external referenced classes
The referenced classes whose documentation is not being generated
during a javadoc run. In other words, these classes are not
passed into the Javadoc tool on the command line. Links in the
generated documentation to those classes are said to be external
references or external links. For example, if you run the Javadoc
tool on only the java.awt package, then any class in java.lang,
such as Object, is an external referenced class. External refer‐
enced classes can be linked to using the -link and -linkoffline
options. An important property of an external referenced class is
that its source comments are normally not available to the
Javadoc run. In this case, these comments cannot be inherited.
SOURCE FILES
The Javadoc tool will generate output originating from four different
types of "source" files: Java language source files for classes
(.java), package comment files, overview comment files, and miscella‐
neous unprocessed files. This section also covers test files and tem‐
plate files that can also be in the source tree, but which you want to
be sure not to document.
Class Source Code Files
Each class or interface and its members can have their own documenta‐
tion comments, contained in a .java file. For more details about these
doc comments, see Documentation Comments.
Package Comment Files
Each package can have its own documentation comment, contained in its
own "source" file, that the Javadoc tool will merge into the package
summary page that it generates. You typically include in this comment
any documentation that applies to the entire package.
To create a package comment file, you have a choice of two files to
place your comments:
o package-info.java - Can contain a package declaration, package
annotations, package comments and Javadoc tags. This file is new
in JDK 5.0, and is preferred over package.html.
o package.html - Can contain only package comments and Javadoc tags,
no package annotations.
A package may have a single package.html file or a single pack‐
age-info.java file but not both. Place either file in the package
directory in the source tree along with your .java files.
package-info.java This file can contain a package comment of the fol‐
lowing structure -- the comment is placed before the package declara‐
tion:
File: java/applet/package-info.java
Note that while the comment separators /** and /* must be present, the
leading asterisks on the intermediate lines can be omitted.
package.html - This file can contain a package comment of the following
structure -- the comment is placed in the <body> element:
File: java/applet/package.html
Notice this is just a normal HTML file and does not include a package
declaration. The content of the package comment file is written in
HTML, like all other comments, with one exception: The documentation
comment should not include the comment separators /** and */ or leading
asterisks. When writing the comment, you should make the first sentence
a summary about the package, and not put a title or any other text
between <body> and the first sentence. You can include package tags; as
with any documentation comment, all block tags must appear after the
main description. If you add a @see tag in a package comment file, it
must have a fully-qualified name. For more details, see the example of
package.html @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html#pack‐
agecomments.
Processing of package comment file - When the Javadoc tool runs, it
will automatically look for the package comment file; if found, the
Javadoc tool does the following:
o Copies the comment for processing. (For package.html, copies all
content between <body> and </body> HTML tags. You can include a
<head> section to put a <title>, source file copyright statement,
or other information, but none of these will appear in the gener‐
ated documentation.)
o Processes any package tags that are present.
o Inserts the processed text at the bottom of the package summary
page it generates, as shown in Package Summary.
o Copies the first sentence of the package comment to the top of the
package summary page. It also adds the package name and this first
sentence to the list of packages on the overview page, as shown in
Overview Summary. The end-of-sentence is determined by the same
rules used for the end of the first sentence of class and member
main descriptions.
Overview Comment File
Each application or set of packages that you are documenting can have
its own overview documentation comment, kept in its own "source" file,
that the Javadoc tool will merge into the overview page that it gener‐
ates. You typically include in this comment any documentation that
applies to the entire application or set of packages.
To create an overview comment file, you can name the file anything you
want, typically overview.html and place it anywhere, typically at the
top level of the source tree. For example, if the source files for the
java.applet package are contained in /home/user/src/java/applet direc‐
tory, you could create an overview comment file at /home/user/src/over‐
view.html.
Notice you can have multiple overview comment files for the same set of
source files, in case you want to run javadoc multiple times on differ‐
ent sets of packages. For example, you could run javadoc once with
-private for internal documentation and again without that option for
public documentation. In this case, you could describe the documenta‐
tion as public or internal in the first sentence of each overview com‐
ment file.
The content of the overview comment file is one big documentation com‐
ment, written in HTML, like the package comment file described previ‐
ously. See that description for details. To re-iterate, when writing
the comment, you should make the first sentence a summary about the
application or set of packages, and not put a title or any other text
between <body> and the first sentence. You can include overview tags;
as with any documentation comment, all tags except in-line tags, such
as {@link}, must appear after the main description. If you add a @see
tag, it must have a fully-qualified name.
When you run the Javadoc tool, you specify the overview comment file
name with the -overview option. The file is then processed similar to
that of a package comment file.
o Copies all content between <body> and </body> tags for processing.
o Processes any overview tags that are present.
o Inserts the processed text at the bottom of the overview page it
generates, as shown in Overview Summary.
o Copies the first sentence of the overview comment to the top of
the overview summary page.
Miscellaneous Unprocessed Files
You can also include in your source any miscellaneous files that you
want the Javadoc tool to copy to the destination directory. These typi‐
cally includes graphic files, example Java source (.java) and class
(.class) files, and self-standing HTML files whose content would over‐
whelm the documentation comment of a normal Java source file.
To include unprocessed files, put them in a directory called doc-files
which can be a subdirectory of any package directory that contains
source files. You can have one such subdirectory for each package. You
might include images, example code, source files, .class files, applets
and HTML files. For example, if you want to include the image of a but‐
ton button.gif in the java.awt.Button class documentation, you place
that file in the /home/user/src/java/awt/doc-files/ directory. Notice
the doc-files directory should not be located at
/home/user/src/java/doc-files because java is not a package -- that is,
it does not directly contain any source files.
All links to these unprocessed files must be hard-coded, because the
Javadoc tool does not look at the files -- it simply copies the direc‐
tory and all its contents to the destination. For example, the link in
the Button.java doc comment might look like:
/**
* This button looks like this:
* <img src="doc-files/Button.gif">
*/
Test Files and Template Files
Some developers have indicated they want to store test files and tem‐
plates files in the source tree near their corresponding source files.
That is, they would like to put them in the same directory, or a subdi‐
rectory, of those source files.
If you run the Javadoc tool by explicitly passing in individual source
filenames, you can deliberately omit test and templates files and pre‐
vent them from being processed. However, if you are passing in package
names or wildcards, you need to follow certain rules to ensure these
test files and templates files are not processed.
Test files differ from template files in that the former are legal,
compilable source files, while the latter are not, but may end with
".java".
Test files - Often developers want to put compilable, runnable test
files for a given package in the same directory as the source files for
that package. But they want the test files to belong to a package other
than the source file package, such as the unnamed package (so the test
files have no package statement or a different package statement from
the source). In this scenario, when the source is being documented by
specifying its package name specified on the command line, the test
files will cause warnings or errors. You need to put such test files in
a subdirectory. For example, if you want to add test files for source
files in com.package1, put them in a subdirectory that would be an
invalid package name (because it contains a hyphen):
com/package1/test-files/
The test directory will be skipped by the Javadoc tool with no warn‐
ings.
If your test files contain doc comments, you can set up a separate run
of the Javadoc tool to produce documentation of the test files by pass‐
ing in their test source filenames with wildcards, such as com/pack‐
age1/test-files/*.java.
Templates for source files - Template files have names that often end
in ".java" and are not compilable. If you have a template for a source
file that you want to keep in the source directory, you can name it
with a dash (such as Buffer-Template.java), or any other illegal Java
character, to prevent it from being processed. This relies on the fact
that the Javadoc tool will only process source files whose name, when
stripped of the ".java" suffix, is actually a legal class name (see
Identifiers @
http://java.sun.com/docs/books/jls/second_edition/html/lexi‐
cal.doc.html#40625).
GENERATED FILES
By default, javadoc uses a standard doclet that generates HTML-format‐
ted documentation. This doclet generates the following kinds of files
(where each HTML "page" corresponds to a separate file). Note that
javadoc generates files with two types of names: those named after
classes/interfaces, and those that are not (such as package-sum‐
mary.html). Files in the latter group contain hyphens to prevent file‐
name conflicts with those in the former group.
Basic Content Pages
o One class or interface page (classname.html) for each class or
interface it is documenting.
o One package page (package-summary.html) for each package it is
documenting. The Javadoc tool will include any HTML text provided
in a file named package.html or package-info.java in the package
directory of the source tree.
o One overview page (overview-summary.html) for the entire set of
packages. This is the front page of the generated document. The
Javadoc tool will include any HTML text provided in a file speci‐
fied with the -overview option. Note that this file is created
only if you pass into javadoc two or more package names. For fur‐
ther explanation, see HTML Frames.)
Cross-Reference Pages
o One class hierarchy page for the entire set of packages (over‐
view-tree.html). To view this, click on "Overview" in the naviga‐
tion bar, then click on "Tree".
o One class hierarchy page for each package (package-tree.html) To
view this, go to a particular package, class or interface page;
click "Tree" to display the hierarchy for that package.
o One "use" page for each package (package-use.html) and a separate
one for each class and interface (class-use/classname.html). This
page describes what packages, classes, methods, constructors and
fields use any part of the given class, interface or package.
Given a class or interface A, its "use" page includes subclasses
of A, fields declared as A, methods that return A, and methods and
constructors with parameters of type A. You can access this page
by first going to the package, class or interface, then clicking
on the "Use" link in the navigation bar.
o A deprecated API page (deprecated-list.html) listing all depre‐
cated names. (A deprecated name is not recommended for use, gener‐
ally due to improvements, and a replacement name is usually given.
Deprecated APIs may be removed in future implementations.)
o A constant field values page (constant-values.html) for the values
of static fields.
o A serialized form page (serialized-form.html) for information
about serializable and externalizable classes. Each such class has
a description of its serialization fields and methods. This infor‐
mation is of interest to re-implementors, not to developers using
the API. While there is no link in the navigation bar, you can get
to this information by going to any serialized class and clicking
"Serialized Form" in the "See also" section of the class comment.
The standard doclet automatically generates a serialized form
page: any class (public or non-public) that implements Serializ‐
able is included, along with readObject and writeObject methods,
the fields that are serialized, and the doc comments from the
@serial, @serialField, and @serialData tags. Public serializable
classes can be excluded by marking them (or their package) with
@serial exclude, and package-private serializable classes can be
included by marking them (or their package) with @serial include.
As of 1.4, you can generate the complete serialized form for pub‐
lic and private classes by running javadoc without specifying the
-private option.
o An index (index-*.html) of all class, interface, constructor,
field and method names, alphabetically arranged. This is interna‐
tionalized for Unicode and can be generated as a single file or as
a separate file for each starting character (such as A-Z for Eng‐
lish).
Support Files
o A help page (help-doc.html) that describes the navigation bar and
the above pages. You can provide your own custom help file to
override the default using -helpfile.
o One index.html file which creates the HTML frames for display.
This is the file you load to display the front page with frames.
This file itself contains no text content.
o Several frame files (*-frame.html) containing lists of packages,
classes and interfaces, used when HTML frames are being displayed.
o A package list file (package-list), used by the -link and -linkof‐
fline options. This is a text file, not HTML, and is not reachable
through any links.
o A style sheet file (stylesheet.css) that controls a limited amount
of color, font family, font size, font style and positioning on
the generated pages.
o A doc-files directory that holds any image, example, source code
or other files that you want copied to the destination directory.
These files are not processed by the Javadoc tool in any manner --
that is, any javadoc tags in them will be ignored. This directory
is not generated unless it exists in the source tree.
HTML Frames
The Javadoc tool will generate either two or three HTML frames, as
shown in the figure below. It creates the minimum necessary number of
frames by omitting the list of packages if there is only one package
(or no packages). That is, when you pass a single package name or
source files (*.java) belonging to a single package as arguments into
the javadoc command, it will create only one frame (C) in the left-hand
column -- the list of classes. When you pass into javadoc two or more
package names, it creates a third frame (P) listing all packages, as
well as an overview page (Detail). This overview page has the filename
overview-summary.html. Thus, this file is created only if you pass in
two or more package names. You can bypass frames by clicking on the "No
Frames" link or entering at overview-summary.html.
If you are unfamiliar with HTML frames, you should be aware that frames
can have focus for printing and scrolling. To give a frame focus, click
on it. Then on many browsers the arrow keys and page keys will scroll
that frame, and the print menu command will print it.
------------------------
|C| Detail | |P| Detail |
| | | | | |
| | | |-| |
| | | |C| |
| | | | | |
| | | | | |
------------------------
javadoc *.java javadoc java.lang java.awt
Load one of the following two files as the starting page depending on
whether you want HTML frames or not:
o index.html (for frames)
o overview-summary.html (for no frames)
Generated File Structure
The generated class and interface files are organized in the same
directory hierarchy that Java source files and class files are orga‐
nized. This structure is one directory per subpackage.
For example, the document generated for the class java.applet.Applet
class would be located at java/applet/Applet.html. The file structure
for the java.applet package follows, given that the destination direc‐
tory is named apidocs. All files that contain the word "frame" appear
in the upper-left or lower-left frames, as noted. All other HTML files
appear in the right-hand frame.
NOTE - Directories are shown in bold. The asterisks (*) indicate the
files and directories that are omitted when the arguments to javadoc
are source filenames (*.java) rather than package names. Also when
arguments are source filenames, package-list is created but is
empty. The doc-files directory will not be created in the destina‐
tion unless it exists in the source tree.
apidocs Top directory
index.html Initial page that sets up HTML frames
* overview-summary.html Lists all packages with first sentence summaries
overview-tree.html Lists class hierarchy for all packages
deprecated-list.html Lists deprecated API for all packages
constant-values.html Lists values of static fields for all packages
serialized-form.html Lists serialized form for all packages
* overview-frame.html Lists all packages, used in upper-left frame
allclasses-frame.html Lists all classes for all packages, used in lower-left frame
help-doc.html Lists user help for how these pages are organized
index-all.html Default index created without -splitindex option
index-files Directory created with -splitindex option
index-<number>.html Index files created with -splitindex option
package-list Lists package names, used only for resolving external refs
stylesheet.css HTML style sheet for defining fonts, colors and positions
java Package directory
applet Subpackage directory
Applet.html Page for Applet class
AppletContext.html Page for AppletContext interface
AppletStub.html Page for AppletStub interface
AudioClip.html Page for AudioClip interface
* package-summary.html Lists classes with first sentence summaries for this package
* package-frame.html Lists classes in this package, used in lower left-hand frame
* package-tree.html Lists class hierarchy for this package
package-use Lists where this package is used
doc-files Directory holding image and example files
class-use Directory holding pages API is used
Applet.html Page for uses of Applet class
AppletContext.html Page for uses of AppletContext interface
AppletStub.html Page for uses of AppletStub interface
AudioClip.html Page for uses of AudioClip interface
src-html Source code directory
java Package directory
applet Subpackage directory
Applet.html Page for Applet source code
AppletContext.html Page for AppletContext source code
AppletStub.html Page for AppletStub source code
AudioClip.html Page for AudioClip source code
a name="generatedapideclarations"/> Generated API Declarations
The Javadoc tool generates a declaration at the start of each class,
interface, field, constructor, and method description for that API
item. For example, the declaration for the Boolean class is:
public final class Boolean
extends Object
implements Serializable
and the declaration for the Boolean.valueOfmethod is:
public static Boolean valueOf(String s)
The Javadoc tool can include the modifiers public, protected, private,
abstract, final, static, transient, and volatile, but not synchronized
or native. These last two modifiers are considered implementation
detail and not part of the API specification.
Rather than relying on the keyword synchronized, APIs should document
their concurrency semantics in the comment's main description, as in "a
single Enumeration cannot be used by multiple threads concurrently".
The document should not describe how to achieve these semantics. As
another example, while Hashtable should be thread-safe, there's no rea‐
son to specify that we achieve this by synchronizing all of its
exported methods. We should reserve the right to synchronize internally
at the bucket level, thus offering higher concurrency.
DOCUMENTATION COMMENTS
The original "Documentation Comment Specification" can be found under
related documentation.
Commenting the Source Code
You can include documentation comments ("doc comments") in the source
code, ahead of declarations for any class, interface, method, construc‐
tor, or field. You can also create doc comments for each package and
another one for the overview, though their syntax is slightly differ‐
ent. Doc comments are also known informally as "Javadoc comments" (but
this term violates its trademark usage). A doc comment consists of the
characters between the characters /** that begin the comment and the
characters */ that end it. Leading asterisks are allowed on each line
and are described further below. The text in a comment can continue
onto multiple lines.
/**
* This is the typical format of a simple documentation comment
* that spans two lines.
*/
To save space you can put a comment on one line:
/** This comment takes up only one line. */
Placement of comments - Documentation comments are recognized only when
placed immediately before class, interface, constructor, method, or
field declarations -- see the class example, method example, and field
example. Documentation comments placed in the body of a method are
ignored. Only one documentation comment per declaration statement is
recognized by the Javadoc tool.
A common mistake is to put an import statement between the class com‐
ment and the class declaration. Avoid this, as the Javadoc tool will
ignore the class comment.
/**
* This is the class comment for the class Whatever.
*/
import com.sun; // MISTAKE - Important not to put import statement here
public class Whatever {
}
A doc comment is composed of a main description followed by a tag sec‐
tion - The main description begins after the starting delimiter /** and
continues until the tag section. The tag section starts with the first
block tag, which is defined by the first @ character that begins a line
(ignoring leading asterisks, white space, and leading separator /**).
It is possible to have a comment with only a tag section and no main
description. The main description cannot continue after the tag section
begins. The argument to a tag can span multiple lines. There can be any
number of tags -- some types of tags can be repeated while others can‐
not. For example, this @see starts the tag section:
/**
* This sentence would hold the main description for this doc comment.
* @see java.lang.Object
*/
Block tags and in-line tags - A tag is a special keyword within a doc
comment that the Javadoc tool can process. There are two kinds of tags:
block tags, which appear as @tag (also known as "standalone tags"), and
in-line tags, which appear within curly braces, as {@tag}. To be inter‐
preted, a block tag must appear at the beginning of a line, ignoring
leading asterisks, white space, and separator (/**). This means you can
use the @ character elsewhere in the text and it will not be inter‐
preted as the start of a tag. If you want to start a line with the @
character and not have it be interpreted, use the HTML entity @.
Each block tag has associated text, which includes any text following
the tag up to, but not including, either the next tag, or the end of
the doc comment. This associated text can span multiple lines. An
in-line tag is allowed and interpreted anywhere that text is allowed.
The following example contains the block tag @deprecated and in-line
tag {@link}.
/**
* @deprecated As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}
*/
Comments are written in HTML - The text must be written in HTML, in
that they should use HTML entities and can use HTML tags. You can use
whichever version of HTML your browser supports; we have written the
standard doclet to generate HTML 3.2-compliant code elsewhere (outside
of the documentation comments) with the inclusion of cascading style
sheets and frames. (We preface each generated file with "HTML 4.0"
because of the frame sets.)
For example, entities for the less-than (<) and greater-than (>) sym‐
bols should be written < and >. Likewise, the ampersand (&) should be
written &. The bold HTML tag <b> is shown in the following example.
Here is a doc comment:
/**
* This is a <b>doc</b> comment.
* @see java.lang.Object
*/
Leading asterisks - When javadoc parses a doc comment, leading asterisk
(*) characters on each line are discarded; blanks and tabs preceding
the initial asterisk (*) characters are also discarded. Starting with
1.4, if you omit the leading asterisk on a line, the leading white
space is no longer removed. This enables you to paste code examples
directly into a doc comment inside a <PRE> tag, and its indentation
will be honored. Spaces are generally interpreted by browsers more uni‐
formly than tabs. Indentation is relative to the left margin (rather
than the separator /** or <PRE> tag).
First sentence - The first sentence of each doc comment should be a
summary sentence, containing a concise but complete description of the
declared entity. This sentence ends at the first period that is fol‐
lowed by a blank, tab, or line terminator, or at the first block tag.
The Javadoc tool copies this first sentence to the member summary at
the top of the HTML page.
Declaration with multiple fields - Java allows declaring multiple
fields in a single statement, but this statement can have only one doc‐
umentation comment, which is copied for all fields. Therefore if you
want individual documentation comments for each field, you must declare
each field in a separate statement. For example, the following documen‐
tation comment doesn't make sense written as a single declaration and
would be better handled as two declarations:
/**
* The horizontal and vertical distances of point (x,y)
*/
public int x, y; // Avoid this
The Javadoc tool generates the following documentation from the above
code:
public int x
The horizontal and vertical distances of point (x,y)
public int y
The horizontal and vertical distances of point (x,y)
Use header tags carefully - When writing documentation comments for
members, it's best not to use HTML heading tags such as <H1> and <H2>,
because the Javadoc tool creates an entire structured document and
these structural tags might interfere with the formatting of the gener‐
ated document. However, it is fine to use these headings in class and
package comments to provide your own structure.
Automatic Copying of Method Comments
The Javadoc tool has the ability to copy or "inherit" method comments
in classes and interfaces under the following two circumstances. Con‐
structors, fields and nested classes do not inherit doc comments.
o Automatically inherit comment to fill in missing text - When a
main description, or @return, @param or @throws tag is missing
from a method comment, the Javadoc tool copies the corresponding
main description or tag comment from the method it overrides or
implements (if any), according to the algorithm below.
More specifically, when a @param tag for a particular parameter is
missing, then the comment for that parameter is copied from the
method further up the inheritance hierarchy. When a @throws tag for
a particular exception is missing, the @throws tag is copied only if
that exception is declared.
This behavior contrasts with version 1.3 and earlier, where the
presence of any main description or tag would prevent all comments
from being inherited.
o Explicitly inherit comment with {@inheritDoc} tag - Insert the
inline tag {@inheritDoc} in a method main description or @return,
@param or @throws tag comment -- the corresponding inherited main
description or tag comment is copied into that spot.
The source file for the inherited method need only be on the path spec‐
ified by -sourcepath for the doc comment to actually be available to
copy. Neither the class nor its package needs to be passed in on the
command line. This contrasts with 1.3.x and earlier releases, where the
class had to be a documented class
Inherit from classes and interfaces - Inheriting of comments occurs in
all three possible cases of inheritance from classes and interfaces:
o When a method in a class overrides a method in a superclass
o When a method in an interface overrides a method in a superinter‐
face
o When a method in a class implements a method in an interface
In the first two cases, for method overrides, the Javadoc tool gener‐
ates a subheading "Overrides" in the documentation for the overriding
method, with a link to the method it is overriding, whether or not the
comment is inherited.
In the third case, when a method in a given class implements a method
in an interface, the Javadoc tool generates a subheading "Specified by"
in the documentation for the overriding method, with a link to the
method it is implementing. This happens whether or not the comment is
inherited.
Algorithm for Inheriting Method Comments - If a method does not have a
doc comment, or has an {@inheritDoc} tag, the Javadoc tool searches for
an applicable comment using the following algorithm, which is designed
to find the most specific applicable doc comment, giving preference to
interfaces over superclasses:
1. Look in each directly implemented (or extended) interface in the
order they appear following the word implements (or extends) in
the method declaration. Use the first doc comment found for this
method.
2. If step 1 failed to find a doc comment, recursively apply this
entire algorithm to each directly implemented (or extended)
interface, in the same order they were examined in step 1.
3. If step 2 failed to find a doc comment and this is a class other
than Object (not an interface):
a. If the superclass has a doc comment for this method, use it.
b. If step 3a failed to find a doc comment, recursively apply
this entire algorithm to the superclass.
JAVADOC TAGS
The Javadoc tool parses special tags when they are embedded within a
Java doc comment. These doc tags enable you to autogenerate a complete,
well-formatted API from your source code. The tags start with an "at"
sign (@) and are case-sensitive -- they must be typed with the upper‐
case and lowercase letters as shown. A tag must start at the beginning
of a line (after any leading spaces and an optional asterisk) or it is
treated as normal text. By convention, tags with the same name are
grouped together. For example, put all @see tags together.
Tags come in two types:
o Block tags - Can be placed only in the tag section that follows
the main description. Block tags are of the form: @tag.
o Inline tags - Can be placed anywhere in the main description or in
the comments for block tags. Inline tags are denoted by curly
braces: {@tag}.
For information about tags we might introduce in future releases, see
Proposed Tags @
http://java.sun.com/j2se/javadoc/proposed-tags.html.
The current tags are:
For custom tags, see the -tag option.
@author name-text
Adds an "Author" entry with the specified name-text to the gener‐
ated docs when the -author option is used. A doc comment may con‐
tain multiple @author tags. You can specify one name per @author
tag or multiple names per tag. In the former case, the Javadoc
tool inserts a comma (,) and space between names. In the latter
case, the entire text is simply copied to the generated document
without being parsed. Therefore, you can use multiple names per
line if you want a localized name separator other than comma.
For more details, see Where Tags Can Be Used and writing @author
tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#@author.
@deprecated deprecated-text
Note: Starting with JDK 5.0, you can deprecate a program element
using the @Deprecated annotation.
Adds a comment indicating that this API should no longer be used
(even though it may continue to work). The Javadoc tool moves the
deprecated-text ahead of the main description, placing it in italics
and preceding it with a bold warning: "Deprecated". This tag is
valid in all doc comments: overview, package, class, interface, con‐
structor, method and field.
The first sentence of deprecated-text should at least tell the user
when the API was deprecated and what to use as a replacement. The
Javadoc tool copies just the first sentence to the summary section
and index. Subsequent sentences can also explain why it has been
deprecated. You should include a {@link} tag (for Javadoc 1.2 or
later) that points to the replacement API:
For more details, see writing @deprecated tags @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html#@dep‐
recated.
o For Javadoc 1.2 and later, use a {@link} tag. This creates the
link in-line, where you want it. For example:
/**
* @deprecated As of JDK 1.1, replaced by {@link #setBounds(int,int,int,int)}
*/
o For Javadoc 1.1, the standard format is to create a @see tag
(which cannot be in-line) for each @deprecated tag.
For more about deprecation, see The @deprecated tag.
{@code text}
Equivalent to <code>{@literal}</code>.
Displays text in code font without interpreting the text as HTML
markup or nested javadoc tags. This enables you to use regular angle
brackets (< and >) instead of the HTML entities (< and >) in doc
comments, such as in parameter types (<Object>), inequalities (3 <
4), or arrows (<-). For example, the doc comment text:
{@code A<B>C}
displays in the generated HTML page unchanged, as:
A<B>C
The noteworthy point is that the <B> is not interpreted as bold and
is in code font.
If you want the same functionality without the code font, use {@lit‐
eral}.
{@docRoot}
Represents the relative path to the generated document's (desti‐
nation) root directory from any generated page. It is useful when
you want to include a file, such as a copyright page or company
logo, that you want to reference from all generated pages. Link‐
ing to the copyright page from the bottom of each page is common.
This {@docRoot} tag can be used both on the command line and in a
doc comment: This tag is valid in all doc comments: overview, pack‐
age, class, interface, constructor, method and field, including the
text portion of any tag (such as @return, @param and @deprecated).
1. On the command line, where the header/footer/bottom are
defined:
javadoc-bottom '<a href="{@docRoot}/copyright.html">Copyright</a>'
NOTE - When using {@docRoot} this way in a make file, some
makefile programs require special escaping for the brace {}
characters. For example, the Inprise MAKE version 5.2 running
on Windows requires double braces: {{@docRoot}}. It also
requires double (rather than single) quotes to enclose argu‐
ments to options such as -bottom (with the quotes around the
href argument omitted).
2. In a doc comment:
/**
* See the <a href="{@docRoot}/copyright.html">Copyright</a>.
*/
The reason this tag is needed is because the generated docs are in
hierarchical directories, as deep as the number of subpackages. This
expression:
<a href="{@docRoot}/copyright.html">
would resolve to:
<a href="../../copyright.html"> for java/lang/Object.java
and
<a href="../../../copyright.html"> for java/lang/ref/Reference.java
@exception class-name description
The @exception tag is a synonym for @throws.
{@inheritDoc}
Inherits (copies) documentation from the "nearest" inheritable
class or implementable interface into the current doc comment at
this tag's location. This allows you to write more general com‐
ments higher up the inheritance tree, and to write around the
copied text.
This tag is valid only in these places in a doc comment:
o In the main description block of a method. In this case, the
main description is copied from a class or interface up the
hierarchy.
o In the text arguments of the @return, @param and @throws tags
of a method. In this case, the tag text is copied from the cor‐
responding tag up the hierarchy.
See Automatic Copying of Method Comments for a more precise descrip‐
tion of how comments are found in the inheritance hierarchy. Note
that if this tag is missing, the comment is or is not automatically
inherited according to rules described in that section.
{@link package.class#member label}
Inserts an in-line link with visible text label that points to
the documentation for the specified package, class or member name
of a referenced class. This tag is valid in all doc comments:
overview, package, class, interface, constructor, method and
field, including the text portion of any tag (such as @return,
@param and @deprecated).
This tag is very simliar to @see -- both require the same references
and accept exactly the same syntax for package.class#member and
label. The main difference is that {@link} generates an in-line link
rather than placing the link in the "See Also" section. Also, the
{@link} tag begins and ends with curly braces to separate it from
the rest of the in-line text. If you need to use "}" inside the
label, use the HTML entity notation }
There is no limit to the number of {@link} tags allowed in a sen‐
tence. You can use this tag in the main description part of any doc‐
umentation comment or in the text portion of any tag (such as @dep‐
recated, @return or @param).
For example, here is a comment that refers to the getComponen‐
tAt(int, int) method:
Use the {@link #getComponentAt(int, int) getComponentAt} method.
From this, the standard doclet would generate the following HTML
(assuming it refers to another class in the same package):
Use the <a href="Component.html#getComponentAt(int, int)">getComponentAt</a> method.
Which appears on the web page as:
Use the getComponentAt method.
You can extend {@link} to link to classes not being documented by
using the -link option.
For more details, see writing {@link} tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#{@link}.
{@linkplain package.class#member label}
Identical to {@link}, except the link's label is displayed in
plain text than code font. Useful when the label is plain text.
Example:
Refer to {@linkplain add() the overridden method}.
This would display as:
Refer to the overridden method.
{@literal text}
Displays text without interpreting the text as HTML markup or
nested javadoc tags. This enables you to use regular angle brack‐
ets (< and >) instead of the HTML entities (< and >) in doc com‐
ments, such as in parameter types (<Object>), inequalities (3 <
4), or arrows (<-). For example, the doc comment text:
{@literal A<B>C}
displays unchanged in the generated HTML page in your browser,
as:
A<B>C The noteworthy point is that the <B> is not interpreted
as bold (and it is not in code font).
If you want the same functionality but with the text in code font,
use {@code}.
@param parameter-name description
Adds a parameter with the specified parameter-name followed by
the specified description to the "Parameters" section. When writ‐
ing the doc comment, you may continue the description onto multi‐
ple lines. This tag is valid only in a doc comment for a method,
constructor or class.
The parameter-name can be the name of a parameter in a method or
constructor, or the name of a type parameter of a class, method or
constructor. Use angle brackets around this parameter name to spec‐
ify the use of a type parameter.
Example of a type parameter of a class:
/**
* @param <E> Type of element stored in a list
*/
public interface List<E> extends Collection<E> {
}
Example of a type parameter of a method:
/**
* @param string the string to be converted
* @param type the type to convert the string to
* @param <T> the type of the element
* @param <V> the value of the element
*/
<T, V extends T> V convert(String string, Class<T> type) {
}
For more details, see writing @param tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#@param.
@return description
Adds a "Returns" section with the description text. This text
should describe the return type and permissible range of values.
This tag is valid only in a doc comment for a method.
For more details, see writing @return tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#@return.
@see reference
Adds a "See Also" heading with a link or text entry that points
to reference. A doc comment may contain any number of @see tags,
which are all grouped under the same heading. The @see tag has
three variations; the third form below is the most common. This
tag is valid in any doc comment: overview, package, class, inter‐
face, constructor, method or field. For inserting an in-line link
within a sentence to a package, class or member, see {@link}.
@see "string"
Adds a text entry for string. No link is generated. The string
is a book or other reference to information not available by
URL. The Javadoc tool distinguishes this from the previous
cases by looking for a double-quote (") as the first charac‐
ter. For example:
@see "The Java Programming Language"
This generates text such as:
See Also:
"The Java Programming Language"
@see <a href="URL#value">label</a>
Adds a link as defined by URL#value. The URL#value is a rela‐
tive or absolute URL. The Javadoc tool distinguishes this from
other cases by looking for a less-than symbol (<) as the first
character. For example:
@see <a href="spec.html#section">Java Spec</a>
This generates a link such as:
See Also:
Java Spec
@see package.class#member label
Adds a link, with visible text label, that points to the docu‐
mentation for the specified name in the Java Language that is
referenced. The label is optional; if omitted, the name
appears instead as the visible text, suitably shortened -- see
How a name is displayed. Use -noqualifier to globally remove
the package name from this visible text. Use the label when
you want the visible text to be different from the auto-gener‐
ated visible text.
Only in version 1.2, just the name but not the label would auto‐
matically appear in <code> HTML tags, Starting with 1.2.2, the
<code> is always included around the visible text, whether or not
a label is used.
o package.class#member is any valid program element name that
is referenced -- a package, class, interface, constructor,
method or field name -- except that the character ahead of
the member name should be a hash character (#). The class
represents any top-level or nested class or interface. The
member represents any constructor, method or field (not a
nested class or interface). If this name is in the docu‐
mented classes, the Javadoc tool will automatically create a
link to it. To create links to external referenced classes,
use the -link option. Use either of the other two @see forms
for referring to documentation of a name that does not
belong to a referenced class. This argument is described at
greater length below under Specifying a Name.
o label is optional text that is visible as the link's label.
The label can contain whitespace. If label is omitted, then
package.class.member will appear, suitably shortened rela‐
tive to the current class and package -- see How a name is
displayed.
o A space is the delimiter between package.class#member and
label. A space inside parentheses does not indicate the
start of a label, so spaces may be used between parameters
in a method.
Example - In this example, an @see tag (in the Character class)
refers to the equals method in the String class. The tag includes
both arguments: the name "String#equals(Object)" and the label
"equals".
/**
* @see String#equals(Object) equals
*/
The standard doclet produces HTML something like this:
<dl>
<dt><b>See Also:</b>
<dd><a href="../../java/lang/String#equals(java.lang.Object)"><code>equals<code></a>
</dl>
Which looks something like this in a browser, where the label is
the visible link text:
See Also:
equals
Specifying a name - This package.class#member name can be either
fully-qualified, such as java.lang.String#toUpperCase() or not,
such as String#toUpperCase() or #toUpperCase(). If less than
fully-qualified, the Javadoc tool uses the normal Java compiler
search order to find it, further described below in Search order
for @see. The name can contain whitespace within parentheses,
such as between method arguments.
Of course the advantage of providing shorter, "partially-quali‐
fied" names is that they are shorter to type and there is less
clutter in the source code. The following table shows the differ‐
ent forms of the name, where Class can be a class or interface,
Type can be a class, interface, array, or primitive, and method
can be a method or constructor.
The following notes apply to the above table:
o The first set of forms (with no class or package) will cause
the Javadoc tool to search only through the current class's
hierarchy. It will find a member of the current class or
interface, one of its superclasses or superinterfaces, or
one of its enclosing classes or interfaces (search steps
1-3). It will not search the rest of the current package or
other packages (search steps 4-5).
o If any method or constructor is entered as a name with no
parentheses, such as getValue, and if there is no field with
the same name, the Javadoc tool will correctly create a link
to it, but will print a warning message reminding you to add
the parentheses and arguments. If this method is overloaded,
the Javadoc tool will link to the first method its search
encounters, which is unspecified.
o Nested classes must be specified as outer.inner, not simply
inner, for all forms.
o As stated, the hash character (#), rather than a dot (.)
separates a member from its class. This enables the Javadoc
tool to resolve ambiguities, since the dot also separates
classes, nested classes, packages, and subpackages. However,
the Javadoc tool is generally lenient and will properly
parse a dot if you know there is no ambiguity, though it
will print a warning.
Search order for @see - the Javadoc tool will process a @see tag
that appears in a source file (.java), package file (package.html
or package-info.java) or overview file (overview.html). In the
latter two files, you must fully-qualify the name you supply with
@see. In a source file, you can specify a name that is
fully-qualified or partially-qualified.
When the Javadoc tool encounters a @see tag in a .java file that
is not fully qualified, it searches for the specified name in the
same order as the Java compiler would (except the Javadoc tool
will not detect certain namespace ambiguities, since it assumes
the source code is free of these errors). This search order is
formally defined in Chapter 6, "Names" of the Java Language Spec‐
ification, Second Edition. The Javadoc tool searches for that
name through all related and imported classes and packages. In
particular, it searches in this order:
1. the current class or interface
2. any enclosing classes and interfaces, searching closest
first
3. any superclasses and superinterfaces, searching closest
first
4. the current package
5. any imported packages, classes and interfaces, searching in
the order of the import statement
The Javadoc tool continues to search recursively through steps
1-3 for each class it encounters until it finds a match. That is,
after it searches through the current class and its enclosing
class E, it will search through E's superclasses before E's
enclosing classes. In steps 4 and 5, the Javadoc tool does not
search classes or interfaces within a package in any specified
order (that order depends on the particular compiler). In step 5,
the Javadoc tool looks in java.lang, since that is automatically
imported by all programs.
The Javadoc tool does not necessarily look in subclasses, nor
will it look in other packages even if their documentation is
being generated in the same run. For example, if the @see tag is
in the java.awt.event.KeyEvent class and refers to a name in the
java.awt package, javadoc does not look in that package unless
that class imports it.
How a name is displayed - If label is omitted, then pack‐
age.class.member appears. In general, it is suitably shortened
relative to the current class and package. By "shortened", we
mean the Javadoc tool displays only the minimum name necessary.
For example, if the String.toUpperCase() method contains refer‐
ences to a member of the same class and to a member of a differ‐
ent class, the class name is displayed only in the latter case,
as shown in the following table.
Use -noqualifier to globally remove the package names.
Examples of @see
The comment to the right shows how the name would be displayed if
the @see tag is in a class in another package, such as
java.applet.Applet.
See also:
@see java.lang.String // String
@see java.lang.String The String class // The String class
@see String // String
@see String#equals(Object) // String.equals(Object)
@see String#equals // String.equals(java.lang.Object)
@see java.lang.Object#wait(long) // java.lang.Object.wait(long)
@see Character#MAX_RADIX // Character.MAX_RADIX
@see <a href="spec.html">Java Spec</a> // Java Spec
@see "The Java Programming Language" // "The Java Programming Language"
You can extend @see to link to classes not being documented by
using the -link option.
For more details, see writing @see tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#@see.
@serial field-description | include | exclude
Used in the doc comment for a default serializable field.
An optional field-description should explain the meaning of the
field and list the acceptable values. If needed, the description can
span multiple lines. The standard doclet adds this information to
the serialized form page.
If a serializable field was added to a class some time after the
class was made serializable, a statement should be added to its main
description to identify at which version it was added.
The include and exclude arguments identify whether a class or pack‐
age should be included or excluded from the serialized form page.
They work as follows:
o A public or protected class that implements Serializable is
included unless that class (or its package) is marked @serial
exclude.
o A private or package-private class that implements Serializable
is excluded unless that class (or its package) is marked
@serial include.
Examples: The javax.swing package is marked @serial exclude (in
package.html or package-info.java). The public class java.secu‐
rity.BasicPermission is marked @serial exclude. The package-private
class java.util.PropertyPermissionCollection is marked @serial
include.
The tag @serial at a class level overrides @serial at a package
level.
For more information about how to use these tags, along with an
example, see "Documenting Serializable Fields and Data for a Class,"
Section 1.6 of the Java Object Serialization Specification. Also see
the Serialization FAQ @
http://java.sun.com/products/jdk/serializa‐
tion/faq/#javadoc_warn_missing, which covers common questions, such
as "Why do I see javadoc warnings stating that I am missing @serial
tags for private fields if I am not running javadoc with the -pri‐
vate switch?". Also see Sun's criteria @
http://java.sun.com/j2se/javadoc/writingapispecs/serialized-crite‐
ria.html for including classes in the serialized form specification.
@serialField field-name field-type field-description
Documents an ObjectStreamField component of a Serializable
class's serialPersistentFields member. One @serialField tag
should be used for each ObjectStreamField component.
@serialData data-description
The data-description documents the types and order of data in the
serialized form. Specifically, this data includes the optional
data written by the writeObject method and all data (including
base classes) written by the Externalizable.writeExternal method.
The @serialData tag can be used in the doc comment for the writeOb‐
ject, readObject, writeExternal, readExternal, writeReplace, and
readResolve methods.
@since since-text
Adds a "Since" heading with the specified since-text to the gen‐
erated documentation. The text has no special internal structure.
This tag is valid in any doc comment: overview, package, class,
interface, constructor, method or field. This tag means that this
change or feature has existed since the software release speci‐
fied by the since-text. For example:
@since 1.5
For source code in the Java platform, this tag indicates the ver‐
sion of the Java platform API specification (not necessarily when
it was added to the reference implementation). Multiple @since
tags are allowed and are treated like multiple @author tags. You
could use multiple tags if the prgram element is used by more
than one API.
@throws class-name description
The @throws and @exception tags are synonyms. Adds a "Throws"
subheading to the generated documentation, with the class-name
and description text. The class-name is the name of the exception
that may be thrown by the method. This tag is valid only in the
doc comment for a method or constructor. If this class is not
fully-specified, the Javadoc tool uses the search order to look
up this class. Multiple @throws tags can be used in a given doc
comment for the same or different exceptions.
To ensure that all checked exceptions are documented, if a @throws
tag does not exist for an exception in the throws clause, the
Javadoc tool automatically adds that exception to the HTML output
(with no description) as if it were documented with @throws tag.
The @throws documentation is copied from an overridden method to a
subclass only when the exception is explicitly declared in the over‐
ridden method. The same is true for copying from an interface method
to an implementing method. You can use {@inheritDoc} to force
@throws to inherit documentation.
For more details, see writing @throws tags @
http://java.sun.com/j2se/javadoc/writingdoccom‐
ments/index.html#@exception.
{@value package.class#field}
When {@value} is used (without any argument) in the doc comment
of a static field, it displays the value of that constant:
/**
* The value of this constant is {@value}.
*/
public static final String SCRIPT_START = "<script>"
When used with argument package.class#field in any doc comment,
it displays the value of the specified constant:
/**
* Evaluates the script starting with {@value #SCRIPT_START}.
*/
public String evalScript(String script) {
}
The argument package.class#field takes a form identical to that
of the @see argument, except that the member must be a static
field.
These values of these constants are also displayed on the Constant
Field Values page.
@version version-text
Adds a "Version" subheading with the specified version-text to
the generated docs when the -version option is used. This tag is
intended to hold the current version number of the software that
this code is part of (as opposed to @since, which holds the ver‐
sion number where this code was introduced). The version-text has
no special internal structure. To see where the version tag can
be used, see Where Tags Can Be Used.
A doc comment may contain multiple @version tags. If it makes sense,
you can specify one version number per @version tag or multiple ver‐
sion numbers per tag. In the former case, the Javadoc tool inserts a
comma (,) and space between names. In the latter case, the entire
text is simply copied to the generated document without being
parsed. Therefore, you can use multiple names per line if you want a
localized name separator other than comma.
For more details, see writing @version tags @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html#@ver‐
sion.
Where Tags Can Be Used
The following sections describe where the tags can be used. Note that
these tags can be used in all doc comments: @see, @since, @deprecated,
{@link}, {@linkplain}, and {@docroot}.
Overview Documentation Tags
Overview tags are tags that can appear in the documentation comment for
the overview page (which resides in the source file typically named
overview.html). Like in any other documentation comments, these tags
must appear after the main description.
NOTE - The {@link} tag has a bug in overview documents in version 1.2
-- the text appears properly but has no link. The {@docRoot} tag does
not currently work in overview documents.
Package Documentation Tags
Package tags are tags that can appear in the documentation comment for
a package (which resides in the source file named package.html or pack‐
age-info.java). The @serial tag can only be used here with the include
or exclude argument.
Class and Interface Documentation Tags
The following are tags that can appear in the documentation comment for
a class or interface. The @serial tag can only be used here with the
include or exclude argument.
An example of a class comment:
/**
* A class representing a window on the screen.
* For example:
* <pre>
* Window win = new Window(parent);
* win.show();
* </pre>
*
* @author Sami Shaio
* @version 1.13, 06/08/06
* @see java.awt.BaseWindow
* @see java.awt.Button
*/
class Window extends BaseWindow {
...
}
Field Documentation Tags
The following are the tags that can appear in the documentation comment
for a field.
An example of a field comment:
/**
* The X-coordinate of the component.
*
* @see #getLocation()
*/
int x = 1263732;
Constructor and Method Documentation Tags
The following are the tags that can appear in the documentation comment
for a constructor or method, except for @return, which cannot appear in
a constructor, and {@inheritDoc}, which has certain restrictions. The
@serialData tag can only be used in the doc comment for certain serial‐
ization methods.
An example of a method doc comment:
/**
* Returns the character at the specified index. An index
* ranges from <code>0</code> to <code>length() - 1</code>.
*
* @param index the index of the desired character.
* @return the desired character.
* @exception StringIndexOutOfRangeException
* if the index is not in the range <code>0</code>
* to <code>length()-1</code>.
* @see java.lang.Character#charValue()
*/
public char charAt(int index) {
...
}
OPTIONS
The javadoc tool uses doclets to determine its output. The Javadoc tool
uses the default standard doclet unless a custom doclet is specified
with the -doclet option. The Javadoc tool provides a set of com‐
mand-line options that can be used with any doclet -- these options are
described below under the sub-heading Javadoc Options. The standard
doclet provides an additional set of command-line options that are
described below under the sub-heading Options Provided by the Standard
Doclet. All option names are case-insensitive, though their arguments
can be case-sensitive.
The options are:
Options shown in italic are the Javadoc core options, which are pro‐
vided by the front end of the Javadoc tool and are available to all
doclets. The standard doclet itself provides the non-italic options.
Javadoc Options
-overview path/filename
Specifies that javadoc should retrieve the text for the overview
documentation from the "source" file specified by path/filename
and place it on the Overview page (overview-summary.html). The
path/filename is relative to the -sourcepath.
While you can use any name you want for filename and place it any‐
where you want for path, a typical thing to do is to name it over‐
view.html and place it in the source tree at the directory that con‐
tains the topmost package directories. In this location, no path is
needed when documenting packages, since -sourcepath will point to
this file. For example, if the source tree for the java.lang package
is /src/classes/java/lang/, then you could place the overview file
at /src/classes/overview.html. See Real World Example.
For information about the file specified by path/filename, see over‐
view comment file.
Note that the overview page is created only if you pass into javadoc
two or more package names. For further explanation, see HTML
Frames.)
The title on the overview page is set by -doctitle.
-public
Shows only public classes and members.
-protected
Shows only protected and public classes and members. This is the
default.
-package
Shows only package, protected, and public classes and members.
-private
Shows all classes and members.
-help
Displays the online help, which lists these javadoc and doclet
command line options.
-doclet class
Specifies the class file that starts the doclet used in generat‐
ing the documentation. Use the fully-qualified name. This doclet
defines the content and formats the output. If the -doclet option
is not used, javadoc uses the standard doclet for generating the
default HTML format. This class must contain the start(Root)
method. The path to this starting class is defined by the
-docletpath option.
For example, to call the MIF doclet, use:
-doclet com.sun.tools.doclets.mif.MIFDoclet
For full, working examples of running a particular doclet, see Run‐
ning the MIF Doclet @
http://java.sun.com/j2se/javadoc/mifdoclet/docs/mifdoclet.html#run‐
ningmifdoclet.
-docletpath classpathlist
Specifies the path to the doclet starting class file (specified
with the -doclet option) and any jar files it depends on. If the
starting class file is in a jar file, then this specifies the
path to that jar file, as shown in the example below. You can
specify an absolute path or a path relative to the current direc‐
tory. If classpathlist contains multiple paths or jar files, they
should be separated with a colon (:) on Solaris and a semi-colon
(;) on Windows. This option is not necessary if the doclet start‐
ing class is already in the search path.
Example of path to jar file that contains the starting doclet class
file. Notice the jar filename is included.
-docletpath /home/user/mifdoclet/lib/mifdoclet.jar
Example of path to starting doclet class file. Notice the class
filename is omitted.
-docletpath /home/user/mifdoclet/classes/com/sun/tools/doclets/mif/
For full, working examples of running a particular doclet, see Run‐
ning the MIF Doclet @
http://java.sun.com/j2se/javadoc/mifdoclet/docs/mifdoclet.html#run‐
ningmifdoclet.
-1.1
This feature has been removed from Javadoc 1.4. There is no
replacement for it. This option created documentation with the
appearance and functionality of documentation generated by
Javadoc 1.1 (it never supported nested classes). If you need this
option, use Javadoc 1.2 or 1.3 instead.
-source release
Specifies the version of source code accepted. The following val‐
ues for release are allowed:
Use the value of release corresponding to that used when compiling
the code with javac.
-sourcepath sourcepathlist
Specifies the search paths for finding source files (.java) when
passing package names or -subpackages into the javadoc command.
The sourcepathlist can contain multiple paths by separating them
with a colon (:). The Javadoc tool will search in all subdirecto‐
ries of the specified paths. Note that this option is not only
used to locate the source files being documented, but also to
find source files that are not being documented but whose com‐
ments are inherited by the source files being documented.
Note that you can use the -sourcepath option only when passing pack‐
age names into the javadoc command -- it will not locate .java files
passed into the javadoc command. (To locate .java files, cd to that
directory or include the path ahead of each file, as shown at Docu‐
menting One or More Classes.) If -sourcepath is omitted, javadoc
uses the class path to find the source files (see -classpath).
Therefore, the default -sourcepath is the value of class path. If
-classpath is omitted and you are passing package names into
javadoc, it looks in the current directory (and subdirectories) for
the source files.
Set sourcepathlist to the root directory of the source tree for the
package you are documenting. For example, suppose you want to docu‐
ment a package called com.mypackage whose source files are located
at:
/home/user/src/com/mypackage/*.java
In this case you would specify the sourcepath to /home/user/src, the
directory that contains com/mypackage, and then supply the package
name com.mypackage:
% javadoc-sourcepath /home/user/src/ com.mypackage
This is easy to remember by noticing that if you concatenate the
value of sourcepath and the package name together and change the dot
to a slash "/", you end up with the full path to the package:
/home/user/src/com/mypackage.
To point to two source paths:
% javadoc-sourcepath /home/user1/src:/home/user2/src com.mypackage
-classpath classpathlist
Specifies the paths where javadoc will look for referenced
classes (.class files) -- these are the documented classes plus
any classes referenced by those classes. The classpathlist can
contain multiple paths by separating them with a colon (:). The
Javadoc tool will search in all subdirectories of the specified
paths. Follow the instructions in class path documentation for
specifying classpathlist.
If -sourcepath is omitted, the Javadoc tool uses -classpath to find
the source files as well as class files (for backward compatibil‐
ity). Therefore, if you want to search for source and class files in
separate paths, use both -sourcepath and -classpath.
For example, if you want to document com.mypackage, whose source
files reside in the directory /home/user/src/com/mypackage, and if
this package relies on a library in /home/user/lib, you would spec‐
ify:
% javadoc-classpath /home/user/lib -sourcepath /home/user/src com.mypackage
As with other tools, if you do not specify -classpath, the Javadoc
tool uses the CLASSPATH environment variable, if it is set. If both
are not set, the Javadoc tool searches for classes from the current
directory.
For an in-depth description of how the Javadoc tool uses -classpath
to find user classes as it relates to extension classes and boot‐
strap classes, see How Classes Are Found.
As a special convenience, a class path element containing a basename
of * is considered equivalent to specifying a list of all the files
in the directory with the extension .jar or .JAR (a java program
cannot tell the difference between the two invocations).
For example, if directory foo contains a.jar and b.JAR, then the
class path element foo/* is expanded to a A.jar:b.JAR, except that
the order of jar files is unspecified. All jar files in the speci‐
fied directory, even hidden ones, are included in the list. A class‐
path entry consisting simply of * expands to a list of all the jar
files in the current directory. The CLASSPATH environment variable,
where defined, will be similarly expanded. Any classpath wildcard
expansion occurs before the Java virtual machine is started -- no
Java program will ever see unexpanded wildcards except by querying
the environment. For example; by invoking System.getenv("CLASS‐
PATH").
-subpackages package1:package2:...
Generates documentation from source files in the specified pack‐
ages and recursively in their subpackages. This option is useful
when adding new subpackages to the source code, as they are auto‐
matically included. Each package argument is any top-level sub‐
package (such as java) or fully qualified package (such as
javax.swing) that does not need to contain source files. Argu‐
ments are separated by colons (on all operating systmes). Wild‐
cards are not needed or allowed. Use -sourcepath to specify where
to find the packages. This option is smart about not processing
source files that are in the source tree but do not belong to the
packages, as described at processing of source files.
For example:
% javadoc-d docs -sourcepath /home/user/src -subpackages java:javax.swing
This command generates documentation for packages named "java" and
"javax.swing" and all their subpackages.
You can use -subpackages in conjunction with -exclude to exclude
specific packages.
-exclude packagename1:packagename2:...
Unconditionally excludes the specified packages and their sub‐
packages from the list formed by -subpackages. It excludes those
packages even if they would otherwise be included by some previ‐
ous or later -subpackages option. For example:
% javadoc-sourcepath /home/user/src -subpackages java -exclude java.net:java.lang
would include java.io, java.util, and java.math (among others),
but would exclude packages rooted at java.net and java.lang.
Notice this excludes java.lang.ref, a subpackage of java.lang).
-bootclasspath classpathlist
Specifies the paths where the boot classes reside. These are nom‐
inally the Java platform classes. The bootclasspath is part of
the search path the Javadoc tool will use to look up source and
class files. See How Classes Are Found. for more details. Sepa‐
rate directories in classpathlist with colons (:).
-extdirs dirlist
Specifies the directories where extension classes reside. These
are any classes that use the Java Extension mechanism. The
extdirs is part of the search path the Javadoc tool will use to
look up source and class files. See -classpath (above) for more
details. Separate directories in dirlist with colons (:).
-verbose
Provides more detailed messages while javadoc is running. Without
the verbose option, messages appear for loading the source files,
generating the documentation (one message per source file), and
sorting. The verbose option causes the printing of additional
messages specifying the number of milliseconds to parse each java
source file.
-quiet
Shuts off non-error and non-warning messages, leaving only the
warnings and errors appear, making them easier to view. Also sup‐
presses the version string.
-breakiterator
Uses the internationalized sentence boundary of
java.text.BreakIterator to determine the end of the first sen‐
tence for English (all other locales already use BreakIterator),
rather than an English language, locale-specific algorithm. By
first sentence, we mean the first sentence in the main descrip‐
tion of a package, class or member. This sentence is copied to
the package, class or member summary, and to the alphabetic
index.
From JDK 1.2 forward, the BreakIterator class is already used to
determine the end of sentence for all languages but English. There‐
fore, the -breakiterator option has no effect except for English
from 1.2 forward. English has its own default algorithm:
o English default sentence-break algorithm - Stops at a period
followed by a space or a HTML block tag, such as <P>.
o Breakiterator sentence-break algorithm - In general, stops at a
period, question mark or exclamation mark followed by a space
if the next word starts with a capital letter. This is meant to
handle most abbreviations (such as "The serial no. is valid",
but won't handle "Mr. Smith"). Doesn't stop at HTML tags or
sentences that begin with numbers or symbols. Stops at the last
period in "../filename", even if embedded in an HTML tag.
NOTE: We have removed from 1.5.0 the breakiterator warning mes‐
sages that were in 1.4.x and have left the default sentence-break
algorithm unchanged. That is, the -breakiterator option is not
the default in 1.5.0, nor do we expect it to become the default.
This is a reversal from our former intention that the default
would change in the "next major release" (1.5.0). This means if
you have not modified your source code to eliminate the breakit‐
erator warnings in 1.4.x, then you don't have to do anything, and
the warnings go away starting with 1.5.0. The reason for this
reversal is because any benefit to having breakiterator become
the default would be outweighed by the incompatible source change
it would require. We regret any extra work and confusion this has
caused.
-locale language_country_variant
Important - The -locale option must be placed ahead (to the left)
of any options provided by the standard doclet or any other
doclet. Otherwise, the navigation bars will appear in English.
This is the only command-line option that is order-dependent.
Specifies the locale that javadoc uses when generating documenta‐
tion. The argument is the name of the locale, as described in
java.util.Locale documentation, such as en_US (English, United
States) or en_US_WIN (Windows variant).
Specifying a locale causes javadoc to choose the resource files of
that locale for messages (strings in the navigation bar, headings
for lists and tables, help file contents, comments in
stylesheet.css, and so forth). It also specifies the sorting order
for lists sorted alphabetically, and the sentence separator to
determine the end of the first sentence. It does not determine the
locale of the doc comment text specified in the source files of the
documented classes.
-encoding name
Specifies the encoding name of the source files, such as
EUCJIS/SJIS. If this option is not specified, the platform
default converter is used.
Also see -docencoding and -charset.
-Jflag
Passes flag directly to the runtime system java that runs
javadoc. Notice there must be no space between the J and the
flag. For example, if you need to ensure that the system sets
aside 32 megabytes of memory in which to process the generated
documentation, then you would call the -Xmx option of java as
follows (-Xms is optional, as it only sets the size of initial
memory, which is useful if you know the minimum amount of memory
required):
% javadoc-J-Xmx32m -J-Xms32m com.mypackage
To tell what version of javadoc you are using, call the "-ver‐
sion" option of java:
% javadoc-J-version
java version "1.2"
Classic VM (build JDK-1.2-V, green threads, sunwjit)
(The version number of the standard doclet appears in its output
stream.)
Options Provided by the Standard Doclet
-d directory
Specifies the destination directory where javadoc saves the gen‐
erated HTML files. (The "d" means "destination.") Omitting this
option causes the files to be saved to the current directory. The
value directory can be absolute, or relative to the current work‐
ing directory. As of 1.4, the destination directory is automati‐
cally created when javadoc is run.
For example, the following generates the documentation for the pack‐
age com.mypackage and saves the results in the /home/user/doc/
directory:
% javadoc-d /home/user/doc com.mypackage
-use
Includes one "Use" page for each documented class and package.
The page describes what packages, classes, methods, constructors
and fields use any API of the given class or package. Given class
C, things that use class C would include subclasses of C, fields
declared as C, methods that return C, and methods and construc‐
tors with parameters of type C.
For example, let's look at what might appear on the "Use" page for
String. The getName() method in the java.awt.Font class returns type
String. Therefore, getName() uses String, and you will find that
method on the "Use" page for String.
Note that this documents only uses of the API, not the implementa‐
tion. If a method uses String in its implementation but does not
take a string as an argument or return a string, that is not consid‐
ered a "use" of String.
You can access the generated "Use" page by first going to the class
or package, then clicking on the "Use" link in the navigation bar.
-version
Includes the @version text in the generated docs. This text is
omitted by default. To tell what version of the Javadoc tool you
are using, use the -J-version option.
-author
Includes the @author text in the generated docs.
-splitindex
Splits the index file into multiple files, alphabetically, one
file per letter, plus a file for any index entries that start
with non-alphabetical characters.
-windowtitle title
Specifies the title to be placed in the HTML <title> tag. This
appears in the window title and in any browser bookmarks
(favorite places) that someone creates for this page. This title
should not contain any HTML tags, as the browser will not prop‐
erly interpret them. Any internal quotation marks within title
may have to be escaped. If -windowtitle is omitted, the Javadoc
tool uses the value of -doctitle for this option.
% javadoc-windowtitle "Java 2 Platform" com.mypackage
-doctitle title
Specifies the title to be placed near the top of the overview
summary file. The title will be placed as a centered, level-one
heading directly beneath the upper navigation bar. The title may
contain html tags and white space, though if it does, it must be
enclosed in quotes. Any internal quotation marks within title may
have to be escaped.
% javadoc-doctitle "Java<sup><font size=\"-2\">TM</font></sup>" com.mypackage
-title title
This option no longer exists. It existed only in Beta versions of
Javadoc 1.2. It has been renamed to -doctitle. This option is
being renamed to make it clear that it defines the document title
rather than the window title.
-header header
Specifies the header text to be placed at the top of each output
file. The header will be placed to the right of the upper naviga‐
tion bar. header may contain HTML tags and white space, though if
it does, it must be enclosed in quotes. Any internal quotation
marks within header may have to be escaped.
% javadoc-header "<b>Java 2 Platform </b><br>v1.4" com.mypackage
-footer footer
Specifies the footer text to be placed at the bottom of each out‐
put file. The footer will be placed to the right of the lower
navigation bar. footer may contain html tags and white space,
though if it does, it must be enclosed in quotes. Any internal
quotation marks within footer may have to be escaped.
-bottom text
Specifies the text to be placed at the bottom of each output
file. The text will be placed at the bottom of the page, below
the lower navigation bar. The text may contain HTML tags and
white space, though if it does, it must be enclosed in quotes.
Any internal quotation marks within text may have to be escaped.
-link extdocURL
Creates links to existing javadoc-generated documentation of
external referenced classes. It takes one argument:
o extdocURL is the absolute or relative URL of the directory con‐
taining the external javadoc-generated documentation you want
to link to. Examples are shown below. The package-list file
must be found in this directory (otherwise, use -linkoffline).
The Javadoc tool reads the package names from the package-list
file and then links to those packages at that URL. When the
Javadoc tool is run, the extdocURL value is copied literally
into the <A HREF> links that are created. Therefore, extdocURL
must be the URL to the directory, not to a file.
You can use an absolute link for extdocURL to enable your docs to
link to a document on any website, or can use a relative link to
link only to a relative location. If relative, the value you pass
in should be the relative path from the destination directory
(specified with -d) to the directory containing the packages
being linked to.
When specifying an absolute link you normally use an http: link.
However, if you want to link to a file system that has no web
server, you can use a file: link -- however, do this only if
everyone wanting to access the generated documentation shares the
same file system.
In all cases, and on all operating systems, you should use a for‐
ward slash as the separator, whether the URL is absolute or rela‐
tive, and "http:" or "file:" based (as specified in the URL Memo
@
http://www.ietf.org/rfc/rfc1738.txt).
Absolute http: based link:
-link http://<host>/<directory>/<directory>/.../<name>
Absolute file: based link:
-link file://<host>/<directory>/<directory>/.../<name>
Relative link:
-link <directory>/<directory>/.../<name>
You can specify multiple -link options in a given javadoc run to
link to multiple documents. Choosing between -linkoffline and -link:
Use -link:
o when using a relative path to the external API document, or
o when using an absolute URL to the external API document, if
your shell allows a program to open a connection to that URL
for reading.
Use -linkoffline:
o when using an absolute URL to the external API document, if
your shell does not allow a program to open a connection to
that URL for reading. This can occur if you are behind a fire‐
wall and the document you want to link to is on the other side.
Example using absolute links to the external docs - Let's say you
want to link to the java.lang, java.io and other Java 2 Platform
packages at http://java.sun.com/j2se/1.5.0/docs/api @
http://java.sun.com/j2se/1.5.0/docs/api, The following command gen‐
erates documentation for the package com.mypackage with links to the
Java 2 Platform packages. The generated documentation will contain
links to the Object class, for example, in the class trees. (Other
options, such as -sourcepath and -d, are not shown.)
% javadoc-link http://java.sun.com/j2se/1.5.0/docs/api com.mypackage
Example using relative links to the external docs - Let's say you
have two packages whose docs are generated in different runs of the
Javadoc tool, and those docs are separated by a relative path. In
this example, the packages are com.apipackage, an API, and com.spi‐
package, an SPI (Service Provide Interface). You want the documenta‐
tion to reside in docs/api/com/apipackage and docs/spi/com/spipack‐
age. Assuming the API package documentation is already generated,
and that docs is the current directory, you would document the SPI
package with links to the API documentation by running:
% javadoc-d ./spi -link ../api com.spipackage
Notice the -link argument is relative to the destination directory
(docs/spi).
Details - The -link option enables you to link to classes referenced
to by your code but not documented in the current javadoc run. For
these links to go to valid pages, you must know where those HTML
pages are located, and specify that location with extdocURL. This
allows, for instance, third party documentation to link to java.*
documentation on http://java.sun.com.
Omit the -link option for javadoc to create links only to API within
the documentation it is generating in the current run. (Without the
-link option, the Javadoc tool does not create links to documenta‐
tion for external references, because it does not know if or where
that documentation exists.)
This option can create links in several places in the generated doc‐
umentation.
Another use is for cross-links between sets of packages: Execute
javadoc on one set of packages, then run javadoc again on another
set of packages, creating links both ways between both sets.
How a Class Must be Referenced - For a link to an external refer‐
enced class to actually appear (and not just its text label), the
class must be referenced in the following way. It is not sufficient
for it to be referenced in the body of a method. It must be refer‐
enced in either an import statement or in a declaration. Here are
examples of how the class java.io.File can be referenced:
o In any kind of import statement: by wildcard import, import
explicitly by name, or automatically import for java.lang.*.
For example, this would suffice:
import java.io.*;
In 1.3.x and 1.2.x, only an explicit import by name works -- a
wildcard import statement does not work, nor does the automatic
import java.lang.*.
o In a declaration:
void foo(File f) {}
The reference and be in the return type or parameter type of a
method, constructor, field, class or interface, or in an imple‐
ments, extends or throws statement.
An important corollary is that when you use the -link option, there
may be many links that unintentionally do not appear due to this
constraint. (The text would appear without a hypertext link.) You
can detect these by the warnings they emit. The most innocuous way
to properly reference a class and thereby add the link would be to
import that class, as shown above.
Package List - The -link option requires that a file named pack‐
age-list, which is generated by the Javadoc tool, exist at the URL
you specify with -link. The package-list file is a simple text file
that lists the names of packages documented at that location. In the
earlier example, the Javadoc tool looks for a file named pack‐
age-list at the given URL, reads in the package names and then links
to those packages at that URL.
For example, the package list for the Java 2 Platform 5.0 API is
located at http://java.sun.com/j2se/1.5.0/docs/api/package-list @
http://java.sun.com/j2se/1.5.0/docs/api/package-list. and starts out
as follows:
java.applet
java.awt
java.awt.color
java.awt.datatransfer
java.awt.dnd
java.awt.event
java.awt.font
etc.
When javadoc is run without the -link option, when it encounters a
name that belongs to an external referenced class, it prints the
name with no link. However, when the -link option is used, the
Javadoc tool searches the package-list file at the specified
extdocURL location for that package name. If it finds the package
name, it prefixes the name with extdocURL.
In order for there to be no broken links, all of the documentation
for the external references must exist at the specified URLs. The
Javadoc tool will not check that these pages exist -- only that the
package-list exists.
Multiple Links - You can supply multiple -link options to link to
any number of external generated documents. Javadoc 1.2 has a
known bug which prevents you from supplying more than one -link com‐
mand. This was fixed in 1.2.2.
Specify a different link option for each external document to link
to:
% javadoc-link extdocURL1 -link extdocURL2 ... -link extdocURLn
com.mypackage
where extdocURL1, extdocURL2, ... extdocURLn point respectively to
the roots of external documents, each of which contains a file named
package-list.
Cross-links - Note that "bootstrapping" may be required when
cross-linking two or more documents that have not previously been
generated. In other words, if package-list does not exist for either
document, when you run the Javadoc tool on the first document, the
package-list will not yet exist for the second document. Therefore,
to create the external links, you must re-generate the first docu‐
ment after generating the second document.
In this case, the purpose of first generating a document is to cre‐
ate its package-list (or you can create it by hand it if you're cer‐
tain of the package names). Then generate the second document with
its external links. The Javadoc tool prints a warning if a needed
external package-list file does not exist.
-linkoffline extdocURL packagelistLoc
This option is a variation of -link; they both create links to
javadoc-generated documentation for external referenced classes.
Use the -linkoffline option when linking to a document on the web
when the Javadoc tool itself is "offline" -- that is, it cannot
access the document through a web connection.
More specifically, use -linkoffline if the external document's pack‐
age-list file is not accessible or does not exist at the extdocURL
location but does exist at a different location, which can be speci‐
fied by packageListLoc (typically local). Thus, if extdocURL is
accessible only on the World Wide Web, -linkoffline removes the con‐
straint that the Javadoc tool have a web connection when generating
the documentation.
Another use is as a "hack" to update docs: After you have run
javadoc on a full set of packages, then you can run javadoc again on
onlya smaller set of changed packages, so that the updated files can
be inserted back into the original set. Examples are given below.
The -linkoffline option takes two arguments -- the first for the
string to be embedded in the <a href> links, the second telling it
where to find package-list:
o extdocURL is the absolute or relative URL of the directory con‐
taining the external javadoc-generated documentation you want
to link to. If relative, the value should be the relative path
from the destination directory (specified with -d) to the root
of the packages being linked to. For more details, see
extdocURL in the -link option.
o packagelistLoc is the path or URL to the directory containing
the package-list file for the external documentation. This can
be a URL (http: or file:) or file path, and can be absolute or
relative. If relative, make it relative to the current direc‐
tory from where javadoc was run. Do not include the pack‐
age-list filename.
You can specify multiple -linkoffline options in a given javadoc
run. (Prior to 1.2.2, it could be specified only once.)
Example using absolute links to the external docs - Let's say you
want to link to the java.lang, java.io and other Java 2 Platform
packages at http://java.sun.com/j2se/1.5.0/docs/api, but your shell
does not have web access. You could open the package-list file in a
browser at http://java.sun.com/j2se/1.5.0/docs/api/package-list @
http://java.sun.com/j2se/1.5.0/docs/api/package-list, save it to a
local directory, and point to this local copy with the second argu‐
ment, packagelistLoc. In this example, the package list file has
been saved to the current directory "." . The following command gen‐
erates documentation for the package com.mypackage with links to the
Java 2 Platform packages. The generated documentation will contain
links to the Object class, for example, in the class trees. (Other
necessary options, such as -sourcepath, are not shown.)
% javadoc-linkoffline http://java.sun.com/j2se/1.5.0/docs/api . com.mypackage
Example using relative links to the external docs - It's not very
common to use -linkoffline with relative paths, for the simple rea‐
son that -link usually suffices. When using -linkoffline, the pack‐
age-list file is generally local, and when using relative links, the
file you are linking to is also generally local. So it is usually
unnecessary to give a different path for the two arguments to
-linkoffline. When the two arguments are identical, you can use
-link. See the -link relative example.
Manually Creating a package-list File - If a package-list file does
not yet exist, but you know what package names your document will
link to, you can create your own copy of this file by hand and spec‐
ify its path with packagelistLoc. An example would be the previous
case where the package list for com.spipackage did not exist when
com.apipackage was first generated. This technique is useful when
you need to generate documentation that links to new external docu‐
mentation whose package names you know, but which is not yet pub‐
lished. This is also a way of creating package-list files for pack‐
ages generated with Javadoc 1.0 or 1.1, where package-list files
were not generated. Likewise, two companies can share their unpub‐
lished package-list files, enabling them to release their
cross-linked documentation simultaneously.
Linking to Multiple Documents - You can include -linkoffline once
for each generated document you want to refer to (each option is
shown on a separate line for clarity):
% javadoc-linkoffline extdocURL1 packagelistLoc1 \
-linkoffline extdocURL2 packagelistLoc2 \
...
Updating docs - Another use for -linkoffline option is useful if
your project has dozens or hundreds of packages, if you have already
run javadoc on the entire tree, and now, in a separate run, you want
to quickly make some small changes and re-run javadoc on just a
small portion of the source tree. This is somewhat of a hack in that
it works properly only if your changes are only to doc comments and
not to declarations. If you were to add, remove or change any decla‐
rations from the source code, then broken links could show up in the
index, package tree, inherited member lists, use page, and other
places.
First, you create a new destination directory (call it update) for
this new small run. Let's say the original destination directory was
named html. In the simplest example, cd to the parent of html. Set
the first argument of -linkoffline to the current directory "." and
set the second argument to the relative path to html, where it can
find package-list, and pass in only the package names of the pack‐
ages you want to update:
% javadoc-d update -linkoffline . html com.mypackage
When the Javadoc tool is done, copy these generated class pages in
update/com/package (not the overview or index), over the original
files in html/com/package.
-linksource
Creates an HTML version of each source file (with line numbers)
and adds links to them from the standard HTML documentation.
Links are created for classes, interfaces, constructors, methods
and fields whose declarations are in a source file. Otherwise,
links are not created, such as for default constructors and gen‐
erated classes.
This option exposes all private implementation details in the
included source files, including private classes, private fields,
and the bodies of private methods, regardless of the -public, -pack‐
age, -protected and -private options. Unless you also use the -pri‐
vate option, not all private classes or interfaces will necessarily
be accessible via links.
Each link appears on the name of the identifier in its declaration.
For example, the link to the source code of the Button class would
be on the word "Button":
public class Button
extends Component
implements Accessible
and the link to the source code of the getLabel() method in the But‐
ton class would be on the word "getLabel":
public String getLabel()-group groupheading packagepattern:packagepattern:...
Separates packages on the overview page into whatever groups you
specify, one group per table. You specify each group with a dif‐
ferent -group option. The groups appear on the page in the order
specified on the command line; packages are alphabetized within a
group. For a given -group option, the packages matching the list
of packagepattern expressions appear in a table with the heading
groupheading.
o groupheading can be any text, and can include white space. This
text is placed in the table heading for the group.
o packagepattern can be any package name, or can be the start of
any package name followed by an asterisk (*). The asterisk is a
wildcard meaning "match any characters". This is the only wild‐
card allowed. Multiple patterns can be included in a group by
separating them with colons (:).
NOTE: If using an asterisk in a pattern or pattern list, the pat‐
tern list must be inside quotes, such as "java.lang*:java.util"
If you do not supply any -group option, all packages are placed in
one group with the heading "Packages". If the all groups do not
include all documented packages, any leftover packages appear in a
separate group with the heading "Other Packages".
For example, the following option separates the four documented
packages into core, extension and other packages. Notice the trail‐
ing "dot" does not appear in "java.lang*" -- including the dot, such
as "java.lang.*" would omit the java.lang package.
% javadoc-group "Core Packages" "java.lang*:java.util"
-group "Extension Packages" "javax.*"
java.lang java.lang.reflect java.util javax.servlet java.new
This results in the groupings:
Core Packages
java.lang java.lang.reflect java.util
Extension Packages
javax.servlet
Other Packages
java.new
-nodeprecated
Prevents the generation of any deprecated API at all in the docu‐
mentation. This does what -nodeprecatedlist does, plus it does
not generate any deprecated API throughout the rest of the docu‐
mentation. This is useful when writing code and you don't want to
be distracted by the deprecated code.
-nodeprecatedlist
Prevents the generation of the file containing the list of depre‐
cated APIs (deprecated-list.html) and the link in the navigation
bar to that page. (However, javadoc continues to generate the
deprecated API throughout the rest of the document.) This is use‐
ful if your source code contains no deprecated API, and you want
to make the navigation bar cleaner.
-nosince
Omits from the generated docs the "Since" sections associated
with the @since tags.
-notree
Omits the class/interface hierarchy pages from the generated
docs. These are the pages you reach using the "Tree" button in
the navigation bar. The hierarchy is produced by default.
-noindex
Omits the index from the generated docs. The index is produced by
default.
-nohelp
Omits the HELP link in the navigation bars at the top and bottom
of each page of output.
-nonavbar
Prevents the generation of the navigation bar, header and footer,
otherwise found at the top and bottom of the generated pages. Has
no affect on the "bottom" option. The -nonavbar option is useful
when you are interested only in the content and have no need for
navigation, such as converting the files to PostScript or PDF for
print only.
-helpfile path/filename
Specifies the path of an alternate help file path/filename that
the HELP link in the top and bottom navigation bars link to.
Without this option, the Javadoc tool automatically creates a
help file help-doc.html that is hard-coded in the Javadoc tool.
This option enables you to override this default. The filename
can be any name and is not restricted to help-doc.html -- the
Javadoc tool will adjust the links in the navigation bar accord‐
ingly. For example:
% javadoc-helpfile /home/user/myhelp.html java.awt
-stylesheetfile path/filename
Specifies the path of an alternate HTML stylesheet file. Without
this option, the Javadoc tool automatically creates a stylesheet
file stylesheet.css that is hard-coded in the Javadoc tool. This
option enables you to override this default. The filename can be
any name and is not restricted to stylesheet.css. For example:
% javadoc-stylesheetfile /home/user/mystylesheet.css com.mypackage
-serialwarn
Generates compile-time warnings for missing @serial tags. By
default, Javadoc 1.2.2 (and later versions) generates no serial
warnings. (This is a reversal from earlier versions.) Use this
option to display the serial warnings, which helps to properly
document default serializable fields and writeExternal methods.
-charset name
Specifies the HTML character set for this document. The name
should be a preferred MIME name as given in the IANA Registry @
http://www.iana.org/assignments/character-sets. For example:
% javadoc-charset "iso-8859-1" mypackage
would insert the following line in the head of every generated
page:
<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
This META tag is described in the HTML standard @
http://www.w3.org/TR/REC-html40/charset.html#h-5.2.2. (4197265
and 4137321)
Also see -encoding and -docencoding.
-docencoding name
Specifies the encoding of the generated HTML files. The name
should be a preferred MIME name as given in the IANA Registry @
http://www.iana.org/assignments/character-sets. If you omit this
option but use -encoding, then the encoding of the generated HTML
files is determined by -encoding. Example:
% javadoc-docencoding "ISO-8859-1" mypackage
Also see -encoding and -charset.
-keywords
Adds HTML meta keyword tags to the generated file for each class.
These tags can help the page be found by search engines that look
for meta tags. (Most search engines that search the entire Inter‐
net do not look at meta tags, because pages can misuse them; but
search engines offered by companies that confine their search to
their own website can benefit by looking at meta tags.)
The meta tags include the fully qualified name of the class and the
unqualified names of the fields and methods. Constructors are not
included because they are identical to the class name. For example,
the class String starts with these keywords:
<META NAME="keywords" CONTENT="java.lang.String class">
<META NAME="keywords" CONTENT="CASE_INSENSITIVE_ORDER">
<META NAME="keywords" CONTENT="length()">
<META NAME="keywords" CONTENT="charAt()">
-tag tagname:Xaoptcmf:"taghead"
Enables the Javadoc tool to interpret a simple, one-argument cus‐
tom block tag @tagname in doc comments. So the Javadoc tool can
"spell-check" tag names, it is important to include a -tag option
for every custom tag that is present in the source code, dis‐
abling (with X) those that are not being output in the current
run.
The colon (:) is always the separator. To use a colon in tagname,
see Use of Colon in Tag Name.
The -tag option outputs the tag's heading taghead in bold, followed
on the next line by the text from its single argument, as shown in
the example below. Like any block tag, this argument's text can con‐
tain inline tags, which are also interpreted. The output is similar
to standard one-argument tags, such as @return and @author. Omitting
taghead causes tagname to appear as the heading.
Placement of tags - The Xaoptcmf part of the argument determines
where in the source code the tag is allowed to be placed, and
whether the tag can be disabled (using X). You can supply either a,
to allow the tag in all places, or any combination of the other let‐
ters: X (disable tag)
a (all)
o (overview)
p (packages)
t (types, that is classes and interfaces)
c (constructors)
m (methods)
f (fields)
Examples of single tags - An example of a tag option for a tag that
that can be used anywhere in the source code is:
-tag todo:a:"To Do:"
If you wanted @todo to be used only with constructors, methods and
fields, you would use:
-tag todo:cmf:"To Do:"
Notice the last colon (:) above is not a parameter separator, but is
part of the heading text (as shown below). You would use either tag
option for source code that contains the tag @todo, such as:
@todo The documentation for this method needs work.
Use of Colon in Tag Name - A colon can be used in a tag name if it
is escaped with a backslash. For this doc comment:
/**
* @ejb:bean
*/
use this tag option:
-tag ejb\\:bean:a:"EJB Bean:"
Spell-checking tag names (Disabling tags) - Some developers put cus‐
tom tags in the source code that they don't always want to output.
In these cases, it is important to list all tags that are present in
the source code, enabling the ones you want to output and disabling
the ones you don't want to output. The presence of X disables the
tag, while its absence enables the tag. This gives the Javadoc tool
enough information to know if a tag it encounters is unknown, proba‐
bly the results of a typo or a misspelling. It prints a warning in
these cases.
You can add X to the placement values already present, so that when
you want to enable the tag, you can simply delete the X. For exam‐
ple, if @todo is a tag that you want to suppress on output, you
would use:
-tag todo:Xcmf:"To Do:"
or, if you'd rather keep it simple:
-tag todo:X
The syntax -tag todo:X works even if @todo is defined by a taglet.
Order of tags - The order of the -tag (and -taglet) options deter‐
mine the order the tags are output. You can mix the custom tags with
the standard tags to intersperse them. The tag options for standard
tags are placeholders only for determining the order -- they take
only the standard tag's name. (Subheadings for standard tags cannot
be altered.) This is illustrated in the following example.
If -tag is missing, then the position of -taglet determines its
order. If they are both present, then whichever appears last on the
command line determines its order. (This happens because the tags
and taglets are processed in the order that they appear on the com‐
mand line. For example, if -taglet and -tag both have the name
"todo", the one that appears last on the command line will determine
its order.
Example of a complete set of tags - This example inserts "To Do"
after "Parameters" and before "Throws" in the output. By using "X",
it also specifies that @example is a tag that might be encountered
in the source code that should not be output during this run. Notice
that if you use @argfile, you can put the tags on separate lines in
an argument file like this (no line continuation characters needed):
-tag param
-tag return
-tag todo:a:"To Do:"
-tag throws
-tag see
-tag example:X
When javadoc parses the doc comments, any tag encountered that is
neither a standard tag nor passed in with -tag or -taglet is consid‐
ered unknown, and a warning is thrown.
The standard tags are initially stored internally in a list in their
default order. Whenever -tag options are used, those tags get
appended to this list -- standard tags are moved from their default
position. Therefore, if a -tag option is omitted for a standard tag,
it remains in its default position.
Avoiding Conflicts - If you want to slice out your own namespace,
you can use a dot-separated naming convention similar to that used
for packages: com.mycompany.todo. Sun will continue to create stan‐
dard tags whose names do not contain dots. Any tag you create will
override the behavior of a tag by the same name defined by Sun. In
other words, if you create a tag or taglet @todo, it will always
have the same behavior you define, even if Sun later creates a stan‐
dard tag of the same name.
Annotations vs. Javadoc Tags - In general, if the markup you want to
add is intended to affect or produce documentation, it should proba‐
bly be a javadoc tag; otherwise, it should be an annotation. See
Comparing Annotations and Javadoc Tags @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html#anno‐
tations
You can also create more complex block tags, or custom inline tags
with the -taglet option.
-taglet class
Specifies the class file that starts the taglet used in generat‐
ing the documentation for that tag. Use the fully-qualified name
for class. This taglet also defines the number of text arguments
that the custom tag has. The taglet accepts those arguments, pro‐
cesses them, and generates the output. For extensive documenta‐
tion with example taglets, see:
o Taglet Overview
Taglets are useful for block or inline tags. They can have any num‐
ber of arguments and implement custom behavior, such as making text
bold, formatting bullets, writing out the text to a file, or start‐
ing other processes.
Taglets can only determine where a tag should appear and in what
form. All other decisions are made by the doclet. So a taglet cannot
do things such as remove a class name from the list of included
classes. However, it can execute side effects, such as printing the
tag's text to a file or triggering another process.
Use the -tagletpath option to specify the path to the taglet. Here
is an example that inserts the "To Do" taglet after "Parameters" and
ahead of "Throws" in the generated pages:
-taglet com.sun.tools.doclets.ToDoTaglet
-tagletpath /home/taglets
-tag return
-tag param
-tag todo
-tag throws
-tag see
Alternatively, you can use the -taglet option in place of its -tag
option, but that may be harder to read.
-tagletpath tagletpathlist
Specifies the search paths for finding taglet class files
(.class). The tagletpathlist can contain multiple paths by sepa‐
rating them with a colon (:). The Javadoc tool will search in all
subdirectories of the specified paths.
-docfilessubdirs
Enables deep copying of "doc-files" directories. In other words,
subdirectories and all contents are recursively copied to the
destination. For example, the directory doc-files/example/images
and all its contents would now be copied. There is also an option
to exclude subdirectories.
-excludedocfilessubdir name1:name2...
Excludes any "doc-files" subdirectories with the given names.
This prevents the copying of SCCS and other source-code-control
subdirectories.
-noqualifier all | packagename1:packagename2:...
Omits qualifying package name from ahead of class names in out‐
put. The argument to -noqualifier is either "all" (all package
qualifiers are omitted) or a colon-separate list of packages,
with wildcards, to be removed as qualifiers. The package name is
removed from places where class or interface names appear.
The following example omits all package qualifiers:
-noqualifier all
The following example omits "java.lang" and "java.io" package quali‐
fiers:
-noqualifier java.lang:java.io
The following example omits package qualifiers starting with "java",
and "com.sun" subpackages (but not "javax"):
-noqualifier java.*:com.sun.*
Where a package qualifier would appear due to the above behavior,
the name can be suitably shortened -- see How a name is displayed.
This rule is in effect whether or not -noqualifier is used.
-notimestamp
Suppresses the timestamp, which is hidden in an HTML comment in
the generated HTML near the top of each page. Useful when you
want to run javadoc on two source bases and diff them, as it pre‐
vents timestamps from causing a diff (which would otherwise be a
diff on every page). The timestamp includes the javadoc version
number, and currently looks like this:
<!-- Generated by javadoc (build 1.5.0-internal) on Tue Jun 22 09:57:24 PDT 2004 -->
-nocomment
Suppress the entire comment body, including the main description
and all tags, generating only declarations. This option enables
re-using source files originally intended for a different pur‐
pose, to produce skeleton HTML documentation at the early stages
of a new project.
COMMAND LINE ARGUMENT FILES
To shorten or simplify the javadoc command line, you can specify one or
more files that themselves contain arguments to the javadoc command
(except -J options). This enables you to create javadoc commands of any
length on any operating system.
An argument file can include javac options and source filenames in any
combination. The arguments within a file can be space-separated or new‐
line-separated. If a filename contains embedded spaces, put the whole
filename in double quotes.
Filenames within an argument file are relative to the current direc‐
tory, not the location of the argument file. Wildcards (*) are not
allowed in these lists (such as for specifying *.java). Use of the '@'
character to recursively interpret files is not supported. The -J
options are not supported because they are passed to the launcher,
which does not support argument files.
When executing javadoc, pass in the path and name of each argument file
with the '@' leading character. When javadoc encounters an argument
beginning with the character `@', it expands the contents of that file
into the argument list.
Example - Single Arg File
You could use a single argument file named "argfile" to hold all
Javadoc arguments:
% javadoc @argfile
This argument file could contain the contents of both files shown in
the next example.
Example - Two Arg Files
You can create two argument files -- one for the Javadoc options and
the other for the package names or source filenames: (Notice the fol‐
lowing lists have no line-continuation characters.)
Create a file named "options" containing:
-d docs-filelist
-use
-splitindex
-windowtitle 'Java 2 Platform v1.3 API Specification'
-doctitle 'Java<sup><font size="-2">TM</font></sup> 2 Platform 5.0 API Specification'
-header '<b>Java 2 Platform </b><br><font size="-1">5.0</font>'
-bottom 'Copyright 1993-2000 Sun Microsystems, Inc. All Rights Reserved.'
-group "Core Packages" "java.*"
-overview /java/pubs/ws/1.5/src/share/classes/overview-core.html
-sourcepath /java/pubs/ws/1.5/src/share/classes
Create a file named "packages" containing:
com.mypackage1
com.mypackage2
com.mypackage3
You would then run javadoc with:
% javadoc @options @packages
Example - Arg Files with Paths
The argument files can have paths, but any filenames inside the files
are relative to the current working directory (not path1 or path2):
% javadoc @path1/options @path2/packages
Example - Option Arguments
Here's an example of saving just an argument to a javadoc option in an
argument file. We'll use the -bottom option, since it can have a
lengthy argument. You could create a file named "bottom" containing its
text argument:
bug or feature</a><br><br>Java is a trademark or registered trademark of
Sun Microsystems, Inc. in the US and other countries.<br>Copyright 1993-2000 Sun
Microsystems, Inc. 901 San Antonio Road,<br>Palo Alto, California, 94303, U.S.A.
All Rights Reserved.</font>'
Then run the Javadoc tool with:
% javadoc-bottom @bottom @packages
Or you could include the -bottom option at the start of the argument
file, and then just run it as:
% javadoc @bottom @packages
NAME
Running
RUNNING JAVADOC
Version Numbers - The version number of javadoc can be determined using
javadoc-J-version. The version number of the standard doclet appears
in its output stream. It can be turned off with -quiet.
Public programmatic interface - To invoke the Javadoc tool from within
programs written in the Java language. This interface is in
com.sun.tools.javadoc.Main (and javadoc is re-entrant). For more
details, see Standard Doclet.
Running Doclets - The instructions given below are for invoking the
standard HTML doclet. To invoke a custom doclet, use the -doclet and
-docletpath options. For full, working examples of running a particular
doclet, see Running the MIF Doclet @
http://java.sun.com/j2se/javadoc/mifdoclet/docs/mifdoclet.html#running‐
mifdoclet.
SIMPLE EXAMPLES
You can run javadoc on entire packages or individual source files. Each
package name has a corresponding directory name. In the following exam‐
ples, the source files are located at /home/src/java/awt/*.java. The
destination directory is /home/html.
Documenting One or More Packages
To document a package, the source files (*.java) for that package must
be located in a directory having the same name as the package. If a
package name is made up of several identifiers (separated by dots, such
as java.awt.color), each subsequent identifier must correspond to a
deeper subdirectory (such as java/awt/color). You may split the source
files for a single package among two such directory trees located at
different places, as long as -sourcepath points to them both -- for
example src1/java/awt/color and src2/java/awt/color.
You can run javadoc either by changing directories (with cd) or by
using -sourcepath option. The examples below illustrate both alterna‐
tives.
o Case 1 - Run recursively starting from one or more packages - This
example uses -sourcepath so javadoc can be run from any directory
and -subpackages (a new 1.4 option) for recursion. It traverses
the subpackages of the java directory excluding packages rooted at
java.net and java.lang. Notice this excludes java.lang.ref, a sub‐
package of java.lang).
% javadoc-d /home/html -sourcepath /home/src -subpackages java -exclude java.net:java.lang
To also traverse down other package trees, append their names to the
-subpackages argument, such as java:javax:org.xml.sax.
o Case 2 - Run on explicit packages after changing to the "root"
source directory - Change to the parent directory of the
fully-qualified package. Then run javadoc, supplying names of one
or more packages you want to document:
% cd /home/src/
% javadoc-d /home/html java.awt java.awt.event
o Case 3 - Run from any directory on explicit packages in a single
directory tree - In this case, it doesn't matter what the current
directory is. Run javadoc supplying -sourcepath with the parent
directory of the top-level package, and supplying names of one or
more packages you want to document:
% javadoc-d /home/html -sourcepath /home/src java.awt java.awt.event
o Case 4 - Run from any directory on explicit packages in multiple
directory trees - This is the same as case 3, but for packages in
separate directory trees. Run javadoc supplying -sourcepath with
the path to each tree's root (colon-separated) and supply names of
one or more packages you want to document. All source files for a
given package do not need to be located under a single root direc‐
tory -- they just need to be found somewhere along the sourcepath.
% javadoc-d /home/html -sourcepath /home/src1:/home/src2 java.awt java.awt.event
Result: All cases generate HTML-formatted documentation for the public
and protected classes and interfaces in packages java.awt and
java.awt.event and save the HTML files in the specified destination
directory (/home/html). Because two or more packages are being gener‐
ated, the document has three HTML frames -- for the list of packages,
the list of classes, and the main class pages.
Documenting One or More Classes
The second way to run the Javadoc tool is by passing in one or more
source files (.java). You can run javadoc either of the following two
ways -- by changing directories (with cd) or by fully-specifying the
path to the .java files. Relative paths are relative to the current
directory. The -sourcepath option is ignored when passing in source
files. You can use command line wildcards, such as asterisk (*), to
specify groups of classes.
o Case 1 - Changing to the source directory - Change to the direc‐
tory holding the .java files. Then run javadoc, supplying names of
one or more source files you want to document.
% cd /home/src/java/awt
% javadoc-d /home/html Button.java Canvas.java Graphics*.java
This example generates HTML-formatted documentation for the
classes Button, Canvas and classes beginning with Graphics.
Because source files rather than package names were passed in as
arguments to javadoc, the document has two frames -- for the list
of classes and the main page.
o Case 2 - Changing to the package root directory - This is useful
for documenting individual source files from different subpackages
off the same root. Change to the package root directory, and sup‐
ply the source files with paths from the root.
% cd /home/src/
% javadoc-d /home/html java/awt/Button.java java/applet/Applet.java
This example generates HTML-formatted documentation for the
classes Button and Applet.
o Case 3 - From any directory - In this case, it doesn't matter what
the current directory is. Run javadoc supplying the absolute path
(or path relative to the current directory) to the .java files you
want to document.
% javadoc-d /home/html /home/src/java/awt/Button.java /home/src/java/awt/Graphics*.java
This example generates HTML-formatted documentation for the class
Button and classes beginning with Graphics.
Documenting Both Packages and Classes
You can document entire packages and individual classes at the same
time. Here's an example that mixes two of the previous examples. You
can use -sourcepath for the path to the packages but not for the path
to the individual classes.
% javadoc-d /home/html -sourcepath /home/src java.awt /home/src/java/applet/Applet.java
This example generates HTML-formatted documentation for the package
java.awt and class Applet. (The Javadoc tool determines the package
name for Applet from the package declaration, if any, in the
Applet.java source file.)
REAL WORLD EXAMPLE
The Javadoc tool has many useful options, some of which are more com‐
monly used than others. Here is effectively the command we use to run
the Javadoc tool on the Java platform API. We use 180MB of memory to
generate the documentation for the 1500 (approx.) public and protected
classes in the Java 2 Platform, Standard Edition, v1.2.
The same example is shown twice -- first as executed on the command
line, then as executed from a makefile. It uses absolute paths in the
option arguments, which enables the same javadoc command to be run from
any directory.
Command Line Example
This command line example is over 900 characters, which is too long for
some shells, such as DOS. You can use a command line argument file (or
write a shell script) to workaround this limitation.
% javadoc-sourcepath /java/jdk/src/share/classes \
-overview /java/jdk/src/share/classes/overview.html \
-d /java/jdk/build/api \
-use \
-splitIndex \
-windowtitle 'Java 2 Platform 5.0 API Specification' \
-doctitle 'Java<sup><font size="-2">TM</font></sup> 2 Platform 5.0 API Specification' \
-header '<b>Java 2 Platform </b><br><font size="-1">5.0</font>' \
-bottom '<font size="-1"><a href="http://java.sun.com/cgi-bin/bugreport.cgi">Submit
a bug or feature</a><br><br>Java is a trademark or registered trademark of Sun Microsystems,
Inc. in the US and other countries.<br>Copyright 1993-1999 Sun Microsystems, Inc.
901 San Antonio Road,<br>Palo Alto, California, 94303, U.S.A. All Rights Reserved.</font>' \
-group "Core Packages" "java.*:com.sun.java.*:org.omg.*" \
-group "Extension Packages" "javax.*" \
-J-Xmx180m \
@packages
where packages is the name of a file containing the packages to
process, such as java.applet java.lang. None of the options should con‐
tain any newline characters between the single quotes. (For example, if
you copy and paste this example, delete the newline characters from the
-bottom option.) See the other notes listed below.
Makefile Example
This is an example of a GNU makefile. For an example of a Windows make‐
file, see creating a makefile for Windows @
http://java.sun.com/j2se/javadoc/faq/index.html#makefiles.
javadoc-sourcepath $(SRCDIR) \ /* Sets path for source files */
-overview $(SRCDIR)/overview.html \ /* Sets file for overview text */
-d /java/jdk/build/api \ /* Sets destination directory */
-use \ /* Adds "Use" files */
-splitIndex \ /* Splits index A-Z */
-windowtitle $(WINDOWTITLE) \ /* Adds a window title */
-doctitle $(DOCTITLE) \ /* Adds a doc title */
-header $(HEADER) \ /* Adds running header text */
-bottom $(BOTTOM) \ /* Adds text at bottom */
-group $(GROUPCORE) \ /* 1st subhead on overview page */
-group $(GROUPEXT) \ /* 2nd subhead on overview page */
-J-Xmx180m \ /* Sets memory to 180MB */
java.lang java.lang.reflect \ /* Sets packages to document */
java.util java.io java.net \
java.applet
WINDOWTITLE = 'Java 2 Platform v1.2 API Specification'
DOCTITLE = 'Java<sup><font size="-2">TM</font></sup> 2 Platform v1.2 API Specification'
HEADER = '<b>Java 2 Platform </b><br><font size="-1">v1.2</font>'
BOTTOM = '<font size="-1"><a href="http://java.sun.com/cgi-bin/bugreport.cgi">Submit
a bug or feature</a><br><br>Java is a trademark or registered trademark
of Sun Microsystems, Inc. in the US and other countries.<br>Copyright 1993-1999
Sun Microsystems, Inc. 901 San Antonio Road,<br>Palo Alto, California, 94303, U.S.A.
All Rights Reserved.</font>'
GROUPCORE = '"Core Packages" "java.*:com.sun.java.*:org.omg.*"'
GROUPEXT = '"Extension Packages" "javax.*"'
SRCDIR = '/java/jdk/1.2/src/share/classes'
Single quotes are used to surround makefile arguments.
NOTES
o If you omit the -windowtitle option, the Javadoc tool copies the
doc title to the window title. The -windowtitle text is basically
the same as the -doctitle but without HTML tags, to prevent those
tags from appearing as raw text in the window title.
o If you omit the -footer option, as done here, the Javadoc tool
copies the header text to the footer.
o Other important options you might want to use but not needed in
this example are -classpath and -link.
TROUBLESHOOTING
General Troubleshooting
o Javadoc FAQ - Commonly-encountered bugs and troubleshooting tips
can be found on the Javadoc FAQ @
http://java.sun.com/j2se/javadoc/faq/index.html#B
o Bugs and Limitations - You can also see some bugs listed at Impor‐
tant Bug Fixes and Changes @
http://java.sun.com/j2se/1.5.0/fixedbugs/index.html.
o Version number - See version numbers.
o Documents only legal classes - When documenting a package, javadoc
only reads files whose names are composed of legal class names.
You can prevent javadoc from parsing a file by including, for
example, a hyphen "-" in its filename.
Errors and Warnings
Error and warning messages contain the filename and line number to the
declaration line rather than to the particular line in the doc comment.
o "error: cannot read: Class1.java" the Javadoc tool is trying to
load the class Class1.java in the current directory. The class
name is shown with its path (absolute or relative), which in this
case is the same as ./Class1.java.
ENVIRONMENT
CLASSPATH
Environment variable that provides the path which javadoc uses to
find user class files. This environment variable is overridden by
the -classpath option. Separate directories with a colon, for
example:
SEE ALSO
o javac
o java
o jdb
o javah
o javap
o Javadoc Home Page @
http://java.sun.com/j2se/javadoc/index.jsp
o How to Write Doc Comments for Javadoc @
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html
o Setting the Class Path
o How Javac and Javadoc Find Classes (tools.jar)
Javadoc is a trademark of Sun Microsystems, Inc. (The javadoc command
itself does not require the trademark symbol.)
07 Aug 2006 javadoc(1)