Javadocs

Javadoc is a tool that generates Java code documentation in the HTML format from Java source code. The documentation is formed from Javadoc comments that are usually placed above classes, methods, or fields. For more information on the correct format of Javadocs, style guide, terms and conventions, refer to How to Write Doc Comments for the Javadoc Tool.

Add a new comment

Add a Javadoc using automatic comments

For documentation comments, IntelliJ IDEA provides completion that is enabled by default.

Type /** before a declaration and press Enter. The IDE auto-completes the doc comment for you.

For information on how to disable this feature, refer to Disable automatic comments.

Add a Javadoc using context actions

Place the caret at the declaration in the editor, press Alt+Enter, and select Add Javadoc from the list.

In Kotlin, the @param and other tags are not generated because the recommended style requires incorporating the description of parameters and return values directly into the documentation comment.

Disable automatic comments

In the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | General | Smart Keys, and clear the Insert documentation comment stub checkbox.

Fix a Javadoc

If a method signature has been changed, IntelliJ IDEA highlights the tag that doesn't match the method signature and suggests a quick-fix. Press Alt+Enter to apply the fix.

You can also update an existing javadoc comment in order to account for the changes in the declaration using the Fix doc comment action:

Place the caret within a class, method, function, or a field, and press Ctrl+Shift+A.
Type fix doc comment and press Enter.

Render Javadocs

IntelliJ IDEA allows you to render Javadocs in the editor. Rendered comments are easier to read, and they don't overload your code with extra tags.

Click in the gutter next to the necessary documentation comment (or press Ctrl+Alt+Q) to toggle the rendered view; click to edit the comment.

Rendered Javadocs allow you to click links to go to the referenced web pages, or view quick documentation for the referenced topics.

To change the font size, right-click a Javadoc in the editor and select Adjust Font Size from the context menu. Note that the rendered comments use the same font size as the quick documentation popup.

Render Javadocs by default

You can configure the IDE to always render Javadocs in the editor.

Right-click the icon in the gutter ( or ) and enable the Render All option.
Alternatively, in the Settings/Preferences dialog Ctrl+Alt+S, select Editor | General | Appearance and enable the Render documentation comments option.

To edit rendered Javadocs, click the icon in the gutter next to the comment.

Generate a Javadoc reference

IntelliJ IDEA provides a utility that enables you to generate a Javadoc reference for your project.

From the main menu, select Tools | Generate JavaDoc.
In the dialog that opens, select a scope — a set of files or directories for which you want to generate the reference, and set the output directory where the generated documentation will be placed.
The Output directory is a mandatory field: you cannot generate a Javadoc file as long it is empty.
Use the slider to define the visibility level of members that will be included in the generated documentation. Select one of the following options:
- Private: to include all classes and members to the reference.
- Package: to include all classes and members except the private ones.
- Protected: to include public and protected classes and members.
- Public: to include only public classes and members.
You can specify a locale (for example en_US.UTF-8), command line arguments, and the maximum heap size.
Click OK to generate the reference.

Specify Generate JavaDoc Scope dialog

The Tools | Generate JavaDoc dialog invokes the JavaDoc utility. The controls of the dialog correspond to the options and tags of this utility.

Item	Description
Generate Javadoc scope	Use this area to specify the subset of files, folders, and packages for which JavaDoc should be generated. This scope can be the whole project, recently modified files, current file, custom scope, and so on.
Include test sources	Include documentation comments for test to the generated JavaDoc.
Include JDK and library sources in -sourcepath	If this checkbox is selected, then paths to the JDK and library sources will be passed to the JavaDoc utility. Refer to documentation for details.
Include link to JDK documentation	If this checkbox is selected, the references to the classes and packages from JDK will turn into links, which corresponds to using the -link option of the JavaDoc utility. This checkbox is only enabled when a link to the online documentation is specified in the Documentation Paths tab of the SDK settings. Refer to JavaDoc documentation for details.
Output directory	Specify the fully qualified path to the directory where the generated documentation will be stored. Type the path manually or click and select the location in the dialog. The specified value is passed to the `-d` parameter of the JavaDoc utility. If the specified directory does not exist in your system, you will be prompted to create it. Note that unless the output directory is specified, the OK button is disabled.
Slider	Specify the visibility level of members that you want to include in the generated documentation: Private: select this level to have all classes and members included. The level corresponds to the `-private` JavaDoc parameter. Package: select this level to have all classes and members except private ones included. The level corresponds to the `-package` JavaDoc parameter. Protected: select this level to have only public and protected classes and members included. The level corresponds to the `-protected` JavaDoc parameter. Public: select this level to have only public classes and members included. The level corresponds to the `-public` JavaDoc parameter.
Generate hierarchy tree	Generate the class hierarchy. If this checkbox is cleared, the `-notree` parameter is passed to JavaDoc.
Generate navigator bar	Generate the navigator bar. If this checkbox is cleared, the `-nonavbar` parameter is passed to JavaDoc.
Generate index	Generate the documentation index. If this checkbox is cleared, the `-noindex` parameter is passed to JavaDoc.
Separate index per letter	Generate a separate index file for each letter. If this checkbox is cleared, the `-splitindex` parameter is passed to JavaDoc. The checkbox is available only if the Generate index checkbox is selected.
@use	Document the use of the class and the package. When selected, the checkbox corresponds to the `-use` JavaDoc parameter.
@author	Include the `@author` paragraphs. When selected, the checkbox corresponds to the `-author` JavaDoc parameter.
@version	Include the `@version` paragraphs. When selected, the checkbox corresponds to the `-version` JavaDoc parameter.
@deprecated	Include the `@deprecated` information. When the checkbox is cleared, the `-nodeprecated` parameter is passed to JavaDoc.
deprecated list	Generate the deprecated list. When the checkbox is cleared, the `-nodeprecatedlist` parameter is passed to JavaDoc. The checkbox is available only if the @deprecated checkbox is selected.
Locale	Type the desired locale.
Other command line arguments	Type additional arguments to be passed to JavaDoc. Use the command line syntax.
Maximum heap size (Mb)	Type the maximum heap size in Mb to be used by Java VM for running JavaDoc.
Open generated documentation in browser	Automatically open the generated JavaDoc in a browser.

View Javadocs in the editor

In IntelliJ IDEA, you can view Javadocs for any symbol or method signature right from the editor. To be able to do that, configure library documentation paths or add downloaded Javadocs to the IDE. For more information, refer to Configure library documentation.

Hover the mouse over the necessary symbol to view its documentation, or place the caret at the symbol, and press Ctrl+Q (View | Quick Documentation).
Press Ctrl+Q again to switch between the popup and the toolbar.

Click in the popup to change the font size, display the quick documentation toolbar, or go to the source code.

For more information, refer to Quick documentation

Troubleshoot

javadoc: error - Malformed locale name: en_US.UTF-8

Clear the Locale field. In the Other command line arguments field, add -encoding utf8 -docencoding utf8 -charset utf8.

-encoding specifies the encoding of the source files. -docencoding specifies the encoding of the output HTML files and -charset is the charset specified in the HTML head section of the output files.

Last modified: 02 August 2022