javadoc(1) javadoc(1)
NAME
javadoc - Java API documentation generator
SYNOPSIS
javadoc [ options ] [ packagenames ] [ sourcefiles ] [
@files ]
PARAMETERS
Parameters can be in any order.
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. javadoc uses
-sourcepath to look for these package
names. javadoc does not recursively tra-
verse subpackages. Wildcards such as
asterisks (*) are not allowed. See EXAM-
PLES, Documenting One or More Packages.
sourcefiles A series of source file names, separated by
spaces, each of which can include paths and
wildcards such as asterisk (*). The path
that precedes the source file name deter-
mines where javadoc will look for it.
(javadoc does not use -sourcepath to look
for these source file names.) For example,
passing in Button.java is identical to
./Button.java. An example source file name
with a full path is
/home/src/java/awt/Graphics*.java. See
EXAMPLES, Documenting One or More Classes.
You can also mix packagenames and source-
files, as in EXAMPLES, Documenting Both
Packages and Classes.
@files One or more files that contain packagenames
and sourcefiles in any order.
DESCRIPTION
javadoc 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, inner classes, interfaces, construc-
tors, methods, and fields.
You can run javadoc on entire packages, individual source
files, or both. In the first case, you pass in as an
argument to javadoc a series of package names. In the
second case, you pass in a series of source (.java) file
names. See EXAMPLES at the end of this document.
As implemented, javadoc requires and relies on the java
compiler to do its job. javadoc calls part of javac to
compile the declarations, ignoring the member implementa-
tion. It builds a rich internal representation of the
classes, including the class hierarchy, and "use" rela-
tionships, then generates the HTML from that. javadoc
also picks up user-supplied documentation from documenta-
tion comments in the source code.
In fact, javadoc will run on .java source files that are
pure stub files with no method bodies. This means you can
write documentation comments and run javadoc in the earli-
est stages of design while creating the API, before writ-
ing the implementation.
Relying on the compiler ensures that the HTML output cor-
responds exactly with the actual implementation, which may
rely on implicit, rather than explicit, source code. For
example, javadoc will document default constructors (sec-
tion 8.6.7 of Java Language Specification) that are pre-
sent in the .class files but not in the source code.
When javadoc builds its internal structure for the docu-
mentation, it loads all referenced classes. Because of
this, javadoc 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 class path of javadoc.
javadoc Doclets
You can customize the content and format of the output of
javadoc by using doclets. javadoc has a default "built-
in" doclet, called the standard doclet, that generates
HTML-formatted API documentation. You can modify or sub-
class the standard doclet, or write your own doclet to
generate HTML, XML, MIF, RTF or whatever output format you
prefer. 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, javadoc uses 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.
Terminology
A few terms have specific meanings within the context of
javadoc:
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 in the Java Language, namely
the name of a package, class, inter-
face, field, constructor, or method.
A name can be fully-qualified, such as
java.lang.String.equals(java.lang.Object),
or partially-qualified, such as
equals(Object).
documented classes The classes and interfaces for which
full documentation is generated during
a javadoc run. To be documented, the
source files must be available, and
either their source filenames or pack-
age names must be passed into the
javadoc command. We also refer to
these as the classes included in the
javadoc run, or the included classes.
referenced classes The classes and interfaces that are
explicitly referred to in the defini-
tion (implementation) of the docu-
mented classes and interfaces. Exam-
ples of references include return
type, parameter type, cast type,
extended class, implemented interface,
imported classes, classes used in
method bodies, and so forth. Classes
referred to in doc comments (such as
@see tags) do not qualify as refer-
enced classes. When javadoc is run,
it loads into memory all of the refer-
enced classes in the bootclasspath and
classpath of javadoc. (javadoc prints
a "Class not found" warning for refer-
enced classes not found.) javadoc can
derive enough information from the
.class files to determine their exis-
tence and the fully qualified names of
their members.
external referenced classes
The referenced classes with documenta-
tion not being generated during a
javadoc run. In other words, these
classes are external to that javadoc
run. Links for names in the documen-
tation to those classes are said to be
external references or external links.
For example, if you run javadoc on
only the java.awt package, then any
class in java.lang, such as Object, is
an external referenced class. Exter-
nal referenced classes can be linked
to using the -link option.
Source Files
javadoc generates output originating from four different
types of "source" files: Java language source files for
classes (.java), package comment files, overview comment
files, and miscellaneous unprocessed files.
Class Source Code Files
Each class or interface and its members can have their own
documentation comment, contained in a .java file. For
more details about these doc commments, see Documentation
Comments below.
Package Comment Files
Each package can have its own documentation comment, con-
tained in its own "source" file, that javadoc will merge
into the package summary page that it generates. You typ-
ically include in this comment any documentation that
applies to the entire package.
To create a package comment file, you must name it
package.html and place it in the package directory in the
source tree along with the .java files. javadoc automati-
cally looks for this filename in this location. Notice
that the filename is identical for all packages.
The content of the package comment file is one big docu-
mentation comment, written in HTML, like all other com-
ments, with one exception, namely, the documentation com-
ment should not include the comment separators /** and */
or leading asterisks. When writing the comment, you
should make the first sentence a summary about the pack-
age, 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 tags except {@link}
must appear after the description. If you add a @see tag
in a package comment file, it must have a fully qualified
name.
When javadoc runs, it automatically looks for this file;
if found, javadoc does the following:
o Copies all content between <body> and </body> tags for
processing.
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 pack-
age 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
descriptions.
Overview Comment File
Each application or set of packages that you are document-
ing can have its own overview documentation comment, kept
in its own "source" file, that javadoc merges into the
overview page that it generates. 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.
Notice that you can have multiple overview comment files
for the same set of source files, in case you want to run
javadoc multiple times on different sets of packages. For
example, if the source files for the java.applet package
are contained in /home/user/src/java/applet directory, you
could create an overview comment file at
/home/user/src/overview.html.
The content of the overview comment file is one big docu-
mentation comment, written in HTML, like the package com-
ment file described previously. See that description for
details. To reiterate, when writing the comment, you
should make the first sentence a summary about the appli-
cation 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 {@link} must appear after the description.
If you add a @see tag, it must have a fully-qualified
name.
When you run javadoc, 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 javadoc to copy to the destination
directory. These typically include graphic files (for
example, Java source (.java) and class (.class) files) and
self-standing HTML files whose content would overwhelm 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 pack-
age directory. 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 button but-
ton.gif in the java.awt.Button class documentation, you
place that file in the /home/user/src/java/awt/doc-files/
directory. All links to these unprocessed files must be
hard-coded, because javadoc does not look at the files; it
only copies the directory and all its contents to the des-
tination. For example, the link in the Button.java doc
comment might look like this:
/**
* This button looks like this:
* <img src="doc-files/Button.gif">
*/
Generated Files
By default, javadoc uses a standard doclet that generates
HTML-formatted documentation. This doclet generates the
following kinds of files (where each HTML "page" corre-
sponds to a separate file). Notice that javadoc generates
files with two types of names: those named after
classes/interfaces, and those that are not (such as pack-
age-summary.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. javadoc includes any HTML text pro-
vided in a file named package.html in the package direc-
tory of the source tree.
o One overview page (overview-summary.html) for the entire
set of packages. This is the front page of the gener-
ated document. javadoc includes any HTML text provided
in a file specified with the -overview option. Notice
that this file is created only if you pass into javadoc
two or more package names. For further explanation, see
HTML Frames below.
Cross-Reference Pages
o One class hierarchy page for the entire set of packages
(overview-tree.html). To view this, click on "Overview"
in the navigation 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
deprecated names. (A deprecated name is not recommended
for use, generally due to improvements, and a replace-
ment name is usually given. Deprecated APIs might be
removed in future implementations.)
o A serialized form page (serialized-form.html) for infor-
mation about serializable and externalizable classes.
Each such class has a description of its serialization
fields and methods. This information 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 description.
o An index (index-*.html) of all class, interface, con-
structor, field and method names, alphabetically
arranged. This is internationalized for Unicode and can
be generated as a single file or as a separate file for
each starting character (such as A-Z for English).
Support Files
o A help page (help-doc.html) that describes the naviga-
tion bar and the above pages. You can provide your own
custom help file to override the default using -help-
file.
o One index.html file that 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 -linkoffline 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 lim-
ited 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
javadoc 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
javadoc generates either two or three HTML frames, as
shown in the figure below. When you pass source files
(*.java) or a single package name as arguments into the
javadoc command, it creates only one frame (C) in the
left-hand column, that is, 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 file
name, 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 as Java source files and
class files. This structure is one directory per subpack-
age.
For example, the document generated for the class
java.applet.Applet would be located at
java/applet/Applet.html. The file structure for the
java.applet package follows, given that the destination
directory 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 file names (*.java)
rather than package names. Also, when arguments are
source file names, package-list is created but is empty.
The doc-files directory is not created in the destination
unless it exists in the source tree.
lb lb. apidocs Top directory
index.html Initial page that sets up HTML frames *
overview-summary.html Packages with first sentence sum-
maries
overview-tree.html Class hierarchy for all packages
deprecated-list.html Deprecated API for all packages
serialized-form.html Serialized form for all packages
* overview-frame.html All packages, used in upper-left
frame
allclasses-frame.html All package classes, lower-left
frame
help-doc.html User help--how pages are organized
index-all.html Default index created w/o-splitindex
index-files Directory created with -splitindex
index-<number>.html Index files created with
-splitindex
package-list Package names--resolving external refs
stylesheet.css HTML style sheet (fonts, colors, etc.)
java Subpackage 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 1st sentence summaries--
package classes
* package-frame.html Package classes, lower left-
hand frame
* package-tree.html Class hierarchy for this
package
package-use Where this package is used
-files Directory holding image & example files
class-use Directory holding pages API is used
Applet.html Page for uses--Applet class
AppletContext.html Page for uses--AppletContext
interface
AppletStub.html Page for uses--AppletStub
interface
AudioClip.html Page for uses--AudioClip
interface
Documentation Comments: Commenting the Source Code
You can include documentation comments in the source code,
ahead of declarations for any entity (classes, interfaces,
methods, constructors, or fields). These are also known
as javadoc comments. A doc comment consists of the char-
acters between the characters /** that begin the comment
and the characters */ that end it. The text can continue
onto multiple lines.
/**
* This is the typical format of a simple documentation comment.
*/
To save space you can put a comment on one line:
/** This comment takes up only one line. */
Documentation comments are recognized only when placed
immediately before class, interface, constructor, method,
or field declarations (see the class example, method exam-
ple, 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 comment and the class declaration. Avoid this, as
javadoc will ignore the class comment.
/**
* This is the class comment for the class Whatever.
*/
import com.sun; // MISTAKE - Important not to put statements here
public class Whatever {
}
A comment is a description followed by tags. The descrip-
tion begins after the starting delimiter /** and continues
until the tag section. The tag section starts with the
first character @ that begins a line (ignoring leading
asterisks and white space). The description cannot con-
tinue after the tag section begins. Any number of tags
can exist, though some types of tags can be repeated while
others cannot. This @see starts the tag section:
/**
* This is a doc comment.
* @see java.lang.Object
*/
Comments are written in HTML. The text must be written in
HTML so that comments can use HTML entities and HTML tags.
You can use whichever version of HTML your browser sup-
ports; the standard doclet is written to generate HTML
3.2-compliant code elsewhere (outside of the documentation
comments) with the inclusion of cascading style sheets and
frames. (Each generated file is prefaced with "HTML 4.0"
because of the frame sets.)
For example, entities for the less-than (<) and greater-
than (>) symbols should be written < and >. Like-
wise, the ampersand (&) should be written &. The bold
HTML tag <b> is shown in the following example:
/**
* This is a <b>doc</b> comment.
* @see java.lang.Object
*/
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. If you omit the leading asterisk on a line,
all leading white space is removed. Therefore, you should
not omit leading asterisks if you want leading white space
to be kept, such as when indenting sample code with the
<pre> tag.
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 followed by a blank, tab, or line termina-
tor, or at the first tag. javadoc copies this first sen-
tence to the member summary at the top of the HTML page.
java allows declaring multiple fields in a single state-
ment, but this statement can have only one documentation
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 documentation comment does not make
sense when 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
javadoc 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 is best not to use HTML heading
tags such as <H1> and <H2>, because javadoc creates an
entire structured document and these structural tags can
interfere with the formatting of the generated document.
However, it is fine to use these headings in class and
package comments to provide your own structure.
Automatic re-use of method comments is also known as
inheriting comments. If a method in a class or interface
has no doc comment or tags, javadoc instead uses the com-
ment and tags from a method it either overrides or imple-
ments, if any. This occurs in three cases:
o When a method in a class overrides a method in a super-
class
o When a method in an interface overrides a method in a
superinterface
o When a method in a class implements a method in an
interface
In the first two cases, if a method m() overrides another
method, javadoc generates a subheading "Overrides" in the
documentation for m(), with a link to the method it is
overriding.
In the third case, if a method m() in a given class imple-
ments a method in an interface, javadoc generates a sub-
heading "Specified by" in the documentation for m(), with
a link to the method it is implementing.
How does it search? For a method in class C, javadoc
searches recursively through all interfaces that class C
implements, then through all superclasses of C. For a
method in interface I, it searches recursively through all
of its superinterfaces. In each case, it copies the first
comment that it finds.
For the specification on documentation comments, see Chap-
ter 18, "Documentation Comments," in the Java Language
Specification, by James Gosling, Bill Joy, and Guy Steele.
javadoc Tags
javadoc parses special tags when they are embedded within
a javadoc comment. These doc tags enable you to autogen-
erate a complete, well-formatted API from your source
code. The tags start with an "at" sign (@) and are case-
sensitive; that is, they must be typed with the uppercase
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, you should group tags with the same name
together. For example, put all @see tags together.
For information about tags might be introduced in future
releases, see Proposed Tags.
The current tags are:
center, box; cbp-1 | cbp-1 l | l . Tag Introduced
in JDK = @author 1.0 {@docRoot} 1.3 @depre-
cated 1.0 @exception 1.0 {@link} 1.2
@param 1.0 @return 1.0 @see 1.0 @serial 1.2 @seri-
alData 1.2 @serialField 1.2 @since 1.1
@throws 1.2 @version 1.0
@author name-text
Adds an "Author" entry with the specified name-text
to the generated docs when the -author option is
used. A doc comment can contain multiple @author
tags. You can specify one name per @author tag or
multiple names per tag. In the former case,
javadoc inserts a comma (,) and space between
names. In the latter case, the entire text is
copied to the generated document without being
parsed. Therefore, use multiple names per line if
you want a localized name separator other than a
comma.
{@docRoot}
Represents the relative path to the generated docu-
ment's (destination) root directory from any gener-
ated 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. Linking to the copyright page from the bot-
tom of each page is common.
This {@docRoot} tag can be used both on the command
line and in a doc comment:
1. On the command line, where the
header/footer/bottom are defined:
javadoc -bottom '<a href="{@docRoot}/copy-
right.html">Copyright</a>'
2. In a doc comment:
/**
* See the <a href="{@docRoot}/copyright.html">Copyright</a>.
*/
The reason this tag is needed is because the gener-
ated 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
@deprecated deprecated-text
Adds a comment indicating that this API should no
longer be used (even though it might continue to
work). javadoc moves the deprecated-text ahead of
the description, placing it in italics and preced-
ing it with a bold warning: "Deprecated".
The first sentence of deprecated-text should at
least tell the user when the API was deprecated and
what to use as a replacement. javadoc 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:
o For javadoc 1.2, 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.
@exception class-name description
The @exception tag is a synonym for @throws.
{@link name label}
Inserts an in-line link that points to the speci-
fied name. This tag accepts exactly the same syn-
tax for name and label as the @see tag, described
below, but generates an in-line link rather than
placing the link in the "See Also" section. This
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 sentence. You can use this tag in the
description part of a documentation comment or in
the text portion of any tag (such as @deprecated,
@return, or @param).
For example, here is a comment that refers to the
getComponentAt(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.
@param parameter-name description
Adds a parameter to the "Parameters" section. The
description can continue on the next line.
@return description
Adds a "Returns" section with the description text.
This text should describe the return type and per-
missible range of values.
@see reference
Adds a "See Also" heading with a link or text entry
that points to reference. A doc comment can con-
tain 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 com-
mon.
@see string
Note: This form is broken in JDK 1.2 (prints none
of the quoted text) but is fixed in JDK 1.2.2.
Adds a text entry for string. No link is generated.
The string is a book or other reference to informa-
tion not available by URL. javadoc distinguishes
this from the previous cases by looking for a dou-
ble-quote (") as the first character. 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 relative or absolute URL. javadoc distin-
guishes 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 documentation for the specified name in the
Java Language. The label is optional; if omitted,
the name appears instead as the visible text, suit-
ably shortened (see How a Name Is Displayed). Use
the label when you want the visible text to be
abbreviated or different from the name.
In JDK 1.2, only the name but not the label auto-
matically appears in <code> HTML tags. Starting
with JDK 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 name in the
Java Language that is referenced (package, class,
interface, constructor, method, or field name),
except that you replace the dot ahead of the mem-
ber name with a hash character (#). If this name
is in the documented classes, javadoc automati-
cally creates 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 white space.
If a label is omitted, then package.class.member
will appear, suitably shortened relative to the
current class and package (see How a Name Is Dis-
played).
o A space is the delimiter between pack-
age.class#member and label. A space inside
parentheses does not indicate the start of a
label, so spaces can be used between parameters
in a method.
In the example below, an @see tag (in the Character
class) refers to the equals method in the String
class. The tag includes both arguments, that is,
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>
The above 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, javadoc uses the normal Java
compiler search order to find it, further described
below in Search order for @see. The name can con-
tain whitespace within parentheses, such as between
method arguments.
The advantage to providing shorter, "partially-
qualified" names is that they require less typing
and make less clutter in the source code. The fol-
lowing table shows the different 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.
box; cbp-1 l . T{ Typical forms for @see pack-
age.class#member T} = Referencing a member of the
current class @see #field @see #method(Type,
Type,...) @see #method(Type argname, Type
argname,...) Referencing another class in the cur-
rent or imported packages @see Class#field @see
Class#method(Type, Type,...) @see
Class#method(Type argname, Type argname,...) @see
Class Referencing another package (fully qualified)
@see package.Class#field @see pack-
age.Class#method(Type, Type,...) @see pack-
age.Class#method(Type argname, Type argname,...)
@see package.Class @see package
The following notes apply to the above table:
o The first set of forms (with no class or package)
will cause javadoc to search only through the
current class's hierarchy. It finds a member of
the current class or interface, one of its super-
classes or superinterfaces, or one of its enclos-
ing 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 no
field with the same name exists, javadoc will
correctly create a link to it, but will print a
warning message reminding you to add the paren-
theses and arguments. If this method is over-
loaded, javadoc links to the first method that
its search encounters, which is unspecified.
o Inner classes must be specified as outer.inner,
not only inner, for all forms.
o As stated, the hash character (#), rather than a
dot (.), separates a member from its class. This
enables javadoc to resolve ambiguities, since the
dot also separates classes, inner classes, pack-
ages, and subpackages. The hash character is
absolutely necessary in the forms above where it
is the first character. However, in other forms,
javadoc is generally lenient and allows a dot if
it does not produce an ambiguity, though it does
print a warning.
Search Order for @see: javadoc will process an @see
tag that appears in a source file (.java), package
file (package.html), 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 javadoc encounters an @see tag in a .java file
that is not fully qualified, it searches for the
specified name in the same order as the Java com-
piler would (except javadoc 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 Specification, modified by the Inner
Classes Specification. javadoc 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
javadoc 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
searches through E's superclasses before E's
enclosing classes. In steps 4 and 5, javadoc does
not search classes or interfaces within a package
in any specified order (that order depends on the
particular compiler). In step 5, javadoc will look
in java.lang,sincethatisautomatically imported by
all programs.
javadoc will 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
java.awt.event.KeyEvent class and refers to a name
in the java.awt package, javadoc will not look in
that package unless that class imports it.
How a Name is Displayed: If label is omitted, then
package.class.member will appear. In general, it
will be suitably shortened relative to the current
class and package. By "shortened", we mean javadoc
will display only the minimum name necessary. For
example, if the String.toUpperCase() method con-
tains references to a member of the same class and
to a member of a different class, the class name
will be displayed only in the latter case:
lb lb lb l lb l. T{
Type
of
Ref-
erence
T} Example Displays As
T{
@see tag
refers
to
member
of
the
same
class
T} T{
@see
String#toLowerCase()
T} T{
toLowerCase()
(omits the class name)
T}
T{
@see
tag
refers
to
member
of a
differ-
ent
class
T} T{
@see
Character#toLowerCase(char)
T} T{
Character.toLowerCase(char)
(includes the class name)
T}
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:
li li
lb l.
Example 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 T{
// String.equals\
(java.lang.Object)
T}
@see java.lang.Object#wait(long) T{
// java.lang.Object.\
wait(long)
T}
@see Character#MAX_RADIX // Character.MAX_RADIX
@see <a href="spec.html">Java Spec</a> // Java Spec
@see "The Java Programming Language" T{
// "The Java Programming \
Language"
T}
@since since-text
Adds a "Since" heading with the specified
since-text
to the generated documentation.
The text has no special internal structure.
This tag means that this change or feature has
existed since the software release specified by the
since-text.
For example:
@since JDK1.1
@serial field-description
Used in the doc comment for a default serializable
field.
An optional field-description augments the doc com-
ment for the field. The combined description must
explain the meaning of the field and list the
acceptable values. If needed, the description can
span multiple lines.
The @since tag should be added to each serializable
field that has been added since the initial version
of a Serializable class.
To get a serialized form for a private class, use
the -private option. Therefore, to generate the
serialized form for all public and private classes,
run javadoc with this -private option.
For more information about how to use these tags,
along with an example, see "Documenting Serializ-
able Fields and Data for a Class," Section 1.6 of
the Java Object Serialization Specification. Also
see the "Serialization FAQ," which covers the ques-
tions, "Why does the javadoc standard doclet gener-
ate many warnings about missing @serial and/or
@serialData tags?" and "Why do I see javadoc warn-
ings stating that I am missing @serial tags for
private fields if I am not running javadoc with the
-private switch?"
@serialField field-name field-type field-description
Documents an ObjectStreamField component of a Seri-
alizable class's serialPersistentFields member.
One @serialField tag should be used for each
ObjectStreamField component.
@serialData data-description
A data-description documents the sequences and
types of data, specifically the optional data writ-
ten by the writeObject method and all data written
by the Externalizable.writeExternal method.
The @serialData tag can be used in the doc comment
for the writeObject, readObject, writeExternal, and
readExternal methods.
@throws class-name description
The @throws and @exception tags are synonyms. Adds
a "Throws" subheading to the generated documenta-
tion, with the class-name and description text.
The class-name is the name of the exception that
can be thrown by the method. If this class is not
fully specified, javadoc uses the search order to
look up this class.
@version version-text
Adds a "Version" subheading with the specified ver-
sion-text to the generated docs when the -version
option is used. The text has no special internal
structure. A doc comment can contain at most one
@version tag. Version normally refers to the ver-
sion of the software (such as the JDK) that con-
tains this class or member.
Where Tags Can Be Used
The following sections describe where the tags can be
used. Notice that these four tags can be used in all doc
comments: @see, @link, @since, @deprecated.
Overview Documentation Tags
Overview tags are tags that can appear in the documenta-
tion comment for the overview page, which resides in the
source file typically named (overview.html). As in any
other documentation comments, these tags must appear after
the description.
NOTE: The {@link} tag has a bug in overview documents in
JDK 1.2. Text appears properly but has no link.
box; cbp-1 l. Overview Tags = @see {@link} @since
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).
box; cbp-1 l. Package Tags = @see {@link} @since
@deprecated
Class and Interface Documentation Tags
The following are tags that can appear in the documenta-
tion comment for a class or interface.
box; cbp-1 l. Class/Interface Tags = @see {@link}
@since @deprecated @author @version
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 1.15, 08/03/00
* @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 documen-
tation comment for a field.
box; cbp-1 l. Field Tags = @see {@link} @since
@deprecated @serial @serialField
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 documen-
tation comment for a constructor or method.
box; cbp-1 l. Method/Constructor Tags = @see
{@link} @since @deprecated @param @return @throws
(@exception) @serialData
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) {
}
Command Line Argument File
To shorten or simplify the javadoc command, you can spec-
ify one or more files that themselves contain one source
filename or package name per line. When executing
javadoc, pass in the filename with the '@' leading charac-
ter to specify it as a file list. When javadoc encounters
an argument beginning with the character it operates on
the names in that file as if they were on the command
line.
For example, you can list all of the package names in a
file named packages. This file might look like:
com.my.package1
com.my.package2
com.my.package3
You could then run javadoc with:
example% javadoc -d apidocs @packages
OPTIONS
The javadoc tool uses doclets to determine its output.
javadoc uses the default standard doclet unless a custom
doclet is specified with the -doclet option. javadoc pro-
vides a set of command-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-insensi-
tive, though their arguments can be case-sensitive.
The options are:
lb lb lb. -1.1 -header -package
-author -help -private -bootclasspath -help-
file -protected -bottom -J -public
-charset -link -serialwarn -class-
path -linkoffline -sourcepath
-d -locale -splitindex -docencoding -nodepre-
cated -stylesheetfile -doclet -nodeprecat-
edlist -title -docletpath -nohelp -use -doc-
title -noindex -verbose -encoding -nonavbar -ver-
sion -extdirs -notree -windowtitle
-footer -overview -group
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 anywhere you want for path, a typical
thing to do is to name it overview.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 pack-
ages, 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 Exam-
ple.
For information about the file specified by
path/filename, see overview comment file.
Notice that the overview page is created only if
you pass into javadoc two or more package names.
For further explanation, see HTML Frames.
-public
Shows only public classes and members.
-protected
Shows only protected and public classes and mem-
bers. 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 generating the documentation. This doclet
defines the content and formats the output. If the
-doclet option is not used, javadoc uses the stan-
dard 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.
-docletpath classpathlist
Specifies the path to the doclet class file that is
specified with the -doclet option. This option is
not necessary if the doclet is already in the
search path.
-1.1 Generates the documentation with the appearance and
functionality of documentation generated by javadoc
1.1. That is, the pages have a gray background,
use images for headers, have bulleted lists instead
of tables, have a flat destination directory struc-
ture, do not contain inherited API, do not use HTML
frames, and do not support inner classes. This
option also automatically splits the index into a
separate file for each letter of the alphabet. If
you want this appearance, this option has the
advantage over javadoc 1.1 of having some bugs
fixed.
Not all options work with the -1.1 option. To find
out which other options are available, execute:
example% javadoc -1.1 -help
The -footer option shown in this list is function-
ally the same as the -bottom option described else-
where on this page. The -title option is function-
ally the same as -doctitle.
-sourcepath sourcepathlist
Specifies the search paths for finding source files
(.java) when passing package names into the javadoc
command. Notice that you can use the -sourcepath
option only when passing package names into the
javadoc command; it does 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 Documenting 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 document a package
called com.mypackage whose source files are located
at:
/home/user/src/com/mypackage/*.java
In this case, you would specify the source path to
/home/user/src, the directory that contains
com/mypackage, and then supply the package name
com.mypackage:
example% javadoc -sourcepath /home/user/src/ com.mypackage
This is easy to remember by noticing that if you
concatenate the value of the source path 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
-classpath classpathlist
Specifies the paths where javadoc looks for refer-
enced classes (.class); these are the documented
classes plus any classes referenced by those
classes. javadoc searches in all subdirectories of
the specified paths. The class path list can con-
tain multiple paths by separating them with a
colon. Follow the instructions in class path docu-
mentation for specifying classpathlist.
If -sourcepath is omitted, javadoc uses -classpath
to find the source files as well as class files
(for backward compatibility). Therefore, if you
want to search for source and class files in sepa-
rate 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
specify:
example% javadoc -classpath /home/user/lib -sourcepath \
/home/user/src com.mypackage
As with other tools, if you do not specify -class-
path, javadoc uses the CLASSPATH environment vari-
able, if it is set. If both are not set, javadoc
searches for classes from the current directory.
For an in-depth description of how javadoc uses
-classpath to find user classes as it relates to
extension classes and bootstrap classes, see How
Classes Are Found.
-bootclasspath classpathlist
Specifies the paths where the boot classes reside.
These are nominally the Java platform classes. The
bootclasspath is part of the search path javadoc
will use to look up source and class files. See
How Classes Are Found for more details. Separate
directories in dirlist 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 javadoc uses 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 mil-
liseconds to parse each java source file.
-locale language_country_variant
Specifies the locale that javadoc uses when gener-
ating documentation. The argument is the name of
the locale, as described in java.util.Locale docu-
mentation, 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 source file encoding name, such as
EUCJIS/SJIS. If this option is not specified, the
platform default converter is used.
-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 gener-
ated documentation, then you would use this flag as
follows:
example% javadoc -J-Xmx32m -J-Xms32m com.mypackage
Options Provided by the Standard Doclet
-d directory
Specifies the destination directory where javadoc
saves the generated 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 working directory. For example, the fol-
lowing generates the documentation for the
com.mypackage package and saves the results in the
/home/user/doc/ directory:
example% 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 constructors with parameters of type C.
For example, look at what might appear on the "Use"
page for String. The getName() method in the
java.awt.Font class returns type String. There-
fore, getName() uses String, and you will find that
method on the "Use" page for String.
Notice that this page documents only uses of the
API, not the implementation. If a method uses
String in its implementation but does not take a
string as an argument or return a string, that is
not considered 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.
-author
Includes the @author text in the generated docs.
-splitindex
Splits the index file into multiple files, alpha-
betically, 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 cannot
properly interpret them. Any internal quotation
marks within title might have to be escaped. If
-windowtitle is omitted, javadoc uses the value of
-doctitle for this option.
-doctitle title
Specifies the title to be placed near the top of
the overview summary file. The title is placed as
a centered, level-one heading directly beneath the
upper navigation bar. title can contain HTML tags
and white space, though if it does, it must be
enclosed in quotes. Any internal quotation marks
within title might have to be escaped.
-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 was 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 is placed to the
right of the upper navigation bar. header can con-
tain HTML tags and white space, though if it does,
it must be enclosed in quotes. Any internal quota-
tion marks within header might have to be escaped.
-footer footer
Specifies the footer text to be placed at the bot-
tom of each output file. The footer is placed to
the right of the lower navigation bar. footer can
contain HTML tags and white space, though if it
does, it must be enclosed in quotes. Any internal
quotation marks within footer might have to be
escaped.
-bottom text
Specifies the text to be placed at the bottom of
each output file. The text is placed at the bottom
of the page, below the lower navigation bar. text
can contain HTML tags and white space, though if it
does, it must be enclosed in quotes. Any internal
quotation marks within text might have to be
escaped.
-link docURL
Creates links to already existing javadoc-generated
documentation of external referenced classes. The
argument docURL is the URL for the javadoc-gener-
ated external documentation you want to link to.
This location can be a relative or absolute URL.
In other words, this option enables you to link to
classes referenced 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
docURL. This allows, for instance, third party
documentation to link to java.* documentation on
http://java.sun.com. 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. A third use is as a "hack" to
update docs: Execute javadoc on a full set of pack-
ages, then run javadoc again on only the smaller
set of changed packages, so that the updated files
can be inserted back into the original set. (This
is done to save time, but can be tricky; if you add
or remove API from the subset, there will be miss-
ing or broken links in the index.)
Use the -link option as follows:
o Omit the -link option for javadoc to create links
only to API within the documentation it is gener-
ating in the current run. (Without the -link
option, javadoc does not create links to documen-
tation for external references, because it does
not know if, or where, that documentation
exists.)
o Include the -link option for javadoc to also
create links to documentation at location docURL
for external referenced classes.
Notice that if the URL is on the World Wide Web,
javadoc must have a web connection in order to
access the package-list when generating the docu-
mentation. If you do not have access, use -linkof-
fline instead.
Package List: The -link option requires that a file
named package-list, which is generated by javadoc,
exist at the URL you specify with -link. The pack-
age-list file is a simple text file that lists the
names of packages documented at that location. How
javadoc uses the package list is described below.
For example, the package list for the Java Platform
1.2 API is located at
http://java.sun.com/products/jdk/1.2/docs/\
api/package-list
It 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 as it
generates documentation, 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, javadoc searches the package-
list file at the specified docURL location for that
package name. If it finds the package name, it
prefixes the name with that URL. (If the URL is
relative and the -d destination directory option is
relative, javadoc prepends the relative path of the
destination directory to the URL so that links work
from the destination directory.)
In order for there to be no broken links, all of
the documentation for the external references must
exist at the specified URLs. javadoc does not
check that these pages exist, only that the pack-
age-list exists.
The package-list file is created but is empty if
the argument to javadoc is source files rather than
packages.
For example, the following command causes javadoc
to look for a package-list file at the given URL,
reads in the package names in that file, and then
uses the given URL when adding links to API in
those external packages:
example% javadoc -link \
http://java.sun.com/products/jdk/1.2/docs/api com.mypackage
Multiple Links: You can supply multiple-link
options to link to any number of external generated
documents. Known Bug: Javadoc 1.2 has a known bug
that prevents you from supplying more than one
-link command. This should be fixed in a future
release.
Specify a different link option for each external
document to link to:
example% javadoc -link docURL1 -link docURL2 ... \
-link docURLn com.mypackage
where docURL1, docURL2, ... docURLn point respec-
tively to the roots of external documents, each of
which contains a file named package-list.
Notice that "bootstrapping" might be required when
cross-linking two or more documents that have not
been previously generated. In other words, if
package-list does not exist for either document,
when you run javadoc on the first document, the
package-list does not yet exist for the second doc-
ument. Therefore, to create the external links,
you must rree-generate the first document after
generating the second document.
In this case, the purpose of first generating a
document is to create its package-list (or you can
create it by hand if you are certain of the package
names). Then generate the second document with its
external links. javadoc prints a warning if a
needed external package-list file does not exist.
Updating Docs: The third use for the -link 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 prop-
erly only if your changes are only to doc comments
and not to signatures. If you were to add, remove,
or change any signatures from the source code, then
broken links could show up in the index, package
tree, inherited member lists, use page, or other
places.
First, you create a new destination directory for
this new small run and set -link and -d to that
same relative path. If the original docs are in a
directory named html:
example% javadoc -d update -linkoffline . html com.mypackage
When javadoc is done, copy these generated files in
update over the original files in html.
Background information: In general, when javadoc
runs, it has the potential to generate links for
names that appear throughout its generated pages,
in signatures, @see tags, {@link} tags, summaries,
hierarchies, the overview, and the index. Some of
these links will go to pages generated in the cur-
rent run, while other links will potentially go to
pages not generated in the current run.
-linkoffline docURL packagelistURL
This option creates links to documentation for
names of external reference classes where:
o docURL is the URL for the root location of the
javadoc-generated external documentation you want
to link to. This location can be a relative or
absolute URL.
o packagelistURL is the URL for the directory con-
taining the package-list file for that documenta-
tion. (You can create this file by hand if you
need to.)
You can specify multiple -linkoffline options in a
given javadoc run. (Prior to javadoc 1.2.2, it
could be specified only once.)
This option is a variation of -link. You can use
-linkoffline if the packages-list file does not
exist at the docURL location at the time you run
javadoc. If you know what package names your docu-
ment will link to, and where that document will
reside, it lets you generate documentation with
those external links prior to when the package-list
file actually exists at that location. This
enables you to use your own copy of package-list to
generate the documentation with the proper links.
This is useful when you need to generate documenta-
tion that links to new external documentation whose
package names you know, but is not yet published.
This enables two companies to release their docu-
mentation simultaneously. It also enables you to
generate documentation that links to external docu-
mentation that has no package-list file (perhaps
because it was generated with javadoc 1.0, 1.1, or
up to 1.2 Beta3).
Notice that this option does not require access to
the documentation URL when you run javadoc. Thus,
if the URL is on the World Wide Web, you do not
need a web connection when generating the documen-
tation.
As shown below, to use this option, specify
docURL1, the location of the javadoc-generated doc-
umentation for external referenced classes, and
packagelistURL1, the location of its package-list
file. If they have the same location, you can just
use -link instead. Include -linkoffline once for
each generated document you want to refer to (this
is shown on two lines only for clarity):
example% javadoc -linkoffline docURL1 packagelistURL1 \
-linkoffline docURL2 packagelistURL2 \
...
For example, the following command adds links with
the URL given as the first argument, and looks for
the package-list file at the path given by the sec-
ond argument.
example% javadoc -linkoffline \
http://java.sun.com/products/jdk/1.2/docs/api \
/jdk/1.2/docs/api/
-group groupheading packagepattern:packagepattern:...
Separates packages on the overview page into what-
ever groups you specify, one group per table. You
specify each group with a different -group option.
The groups appear on the page in the order speci-
fied 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 pattern list must be inside quotes, such
as "java.lang*:java.util".
If you do not supply any -group option, all pack-
ages 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 Pack-
ages".
For example, the following option separates the
four documented packages into core, extension, and
other packages. Notice the trailing "dot" does not
appear in "java.lang*"; including the dot, such as
"java.lang.*", would omit the java.lang package:
example% 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 documentation. This does what -nodepre-
catedlist does, plus it does not generate any dep-
recated API throughout the rest of the documenta-
tion. This is useful when writing code and you do
not want to be distracted by the deprecated code.
-nodeprecatedlist
Prevents the generation of the file containing the
list of deprecated APIs (deprecated-list.html) and
the link in the navigation bar to that page. (How-
ever, javadoc continues to generate the deprecated
API throughout the rest of the document.) This is
useful if your source code contains no deprecated
API, and you want to make the navigation bar
cleaner.
-notree
Omits the class/interface hierarchy from the gener-
ated docs. 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 effect on
the "bottom" option. The -nonavbar option is use-
ful 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, javadoc automatically creates a help file
help-doc.html that is hard-coded in javadoc. This
option enables you to override this default. The
file name can be any name and is not restricted to
help-doc.html; javadoc will adjust the links in the
navigation bar accordingly. For example:
example% javadoc -helpfile /home/doc/myhelp.html java.awt
-stylesheetfile path/filename
Specifies the path of an alternate HTML stylesheet
file. Without this option, javadoc automatically
creates a stylesheet file, stylesheet.css, that is
hard-coded in javadoc. This option enables you to
override this default. The file name can be any
name and is not restricted to stylesheet.css. For
example:
example% javadoc -stylesheetfile \
/home/doc/mystylesheet.css java.awt
-serialwarn
Generates compile-time warnings for missing @serial
tags. By default, javadoc 1.2.2 (and later ver-
sions) 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.
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-885 9-1">
This META tag is described in the HTML standard
(4197265 and 4137321).
-docencoding name
Specifies the encoding of the generated HTML files.
EXAMPLES
You can run javadoc on entire packages or individual
classes. Each package name has a corresponding directory
name. In the following examples, 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 sev-
eral identifiers (separated by dots), each identifier rep-
resents a different directory. Thus, all java.awt classes
must reside in a directory named java/awt/. You can run
javadoc either of the following two ways: by changing
directories (with cd) or by using -sourcepath option. You
cannot use wildcards to specify groups of packages.
o Case 1 Changing to the package 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:
example% cd /home/src/
example% javadoc -d /home/html java.awt java.awt.event
o Case 2 From any directory: In this case, it does not
matter what the current directory is. Run javadoc sup-
plying -sourcepath with the parent directory of the
fully qualified package, and supply names of one or more
packages you want to document:
example% javadoc -d /home/html -sourcepath /home/src \
java.awt java.awt.event
Both 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 generated, the document has
three frames: for the list of packages, the list of
classes, and the main page.
Documenting One or More Classes
The second way to run javadoc 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 -sour-
cepath 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
directory holding the .java files. Then run javadoc,
supplying names of one or more source files you want to
document.
example% cd /home/src/java/awt
example% 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 docu-
ment 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 dif-
ferent subpackages off the same root. Change to the
package root directory, and supply the source files with
paths from the root.
example% cd /home/src/
example% 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 does not
matter what the current directory is. Run javadoc, sup-
plying the absolute path (or path relative to the cur-
rent directory) to the .java files you want to document:
example% 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 is an example that mixes the two pre-
vious examples. You can use -sourcepath for the path to
the packages but not for the path to the individual
classes:
example% 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. (javadoc deter-
mines the package name for Applet from the package decla-
ration, if any, in the Applet.java source file.)
Real World Example
javadoc has many useful options, some of which are more
commonly used than others. Here is effectively the com-
mand you need to run javadoc on the Java platform API,
using makefile variables (except not all packages to be
documented are listed):
example% javadoc -sourcepath /jdk/src/share/classes /* Path for
source files */
-d /jdk/build/api /* 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) /* Core heading for overview page */
-group $(GROUPEXT) /* Ext heading for overview page */
-overview $ (SCRDIR) /overview.html /* For overview text */
-J-Xmx180m /* For 180MB memory */
java.lang java.lang.reflect /* Packages to document */
java.util java.io java.net java.applet
WINDOWTITLE = 'Java Platform 1.2 Final API Specification'
DOCTITLE = 'Java<sup><font size="-2">TM</font></sup> Platform 1.2 \
Final API Specification'
HEADER = '<b>Java Platform 1.2</b><br><font size="-1">Final</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 1993-1998 Sun Microsystems, Inc. 901 San \
Antonio Road,<br>Palo Alto, California, 94303, U.S.A.\
</font>'
GROUPCORE = '"Core Packages" "java.*:com.sun.java.*:org.omg.*"
GROUPEXT = '"Extension Packages" "javax.*"'
SRCDIR = '/java/jdk/1.2/src/share/classes'
If you omit the -windowtitle option, javadoc copies
the doc title to the window title. The -windowtitle
option would not be needed except that the doc
title contains HTML tags (which would appear as raw
text in the window title).
If you omit the -footer option, as done here,
javadoc copies the header text to the footer.
Other important options not needed in this example
are -classpath and -link.
ENVIRONMENT VARIABLES
CLASSPATH Environment variable that provides the
path that javadoc uses to find user
class files. This environment vari-
able is overridden by the -classpath
option. Separate your directories
with a colon, as for example:
.:/Users/vlh/classes:/Users/Shared/classes
SEE ALSO
javac(1), java(1), jdb(1), javah(1), javap(1)
See (or search java.sun.com) for the following:
The Javadoc Home Page @
http://java.sun.com/prod-
ucts/jdk/javadoc/index.html
Javadoc Enhancements @
http://java.sun.com/j2se/1.3/docs/tooldocs/javadoc/index.html
Javadoc FAQ @
http://java.sun.com/products/jdk/javadoc/faq.html
How to Write Doc Comments for Javadoc @
http://java.sun.com/products/jdk/javadoc/writ-
ingdoccomments.html
How Classes Are Found @
http://java.sun.com/j2se/1.3/docs/tooldocs/find-
ingclasses.html#srcfiles
14 July 2000 javadoc(1)