Module jdk.javadoc

Package jdk.javadoc.doclet

The Doclet API provides an environment which, in conjunction with the Language Model API and Compiler Tree API, allows clients to inspect the source-level structures of programs and libraries, including API comments embedded in the source.

The standard doclet can be used to generate HTML-formatted documentation. It supports user-defined taglets, which can be used to generate customized output for user-defined tags in documentation comments.

Note: The declarations in this package supersede those in the older package com.sun.javadoc. For details on the mapping of old types to new types, see the Migration Guide.

Doclets are invoked by javadoc and this API can be used to write out program information to files. For example, the standard doclet is invoked by default, to generate HTML documentation.

The invocation is defined by the interface Doclet -- the run interface method, defines the entry point.

    public boolean run(DocletEnvironment environment)
The DocletEnvironment instance holds the environment that the doclet will be initialized with. From this environment all other information can be extracted, in the form of elements. One can further use the APIs and utilities described by Language Model API to query Elements and Types.


An element is considered to be selected, if the selection controls allow it to be documented. (Note that synthetic elements are never selected.)
The set of elements specified by the user are considered to be specified elements. Specified elements provide the starting points for determining the included elements to be documented.
An element is considered to be included, if it is specified if it contains a specified element, or it is enclosed in a specified element, and is selected. Included elements will be documented.


Javadoc selection control can be specified with these options as follows:
  • --show-members:value and --show-types:value can be used to filter the members, with the following values:
    • public -- considers only public elements
    • protected -- considers public and protected elements
    • package -- considers public, protected and package private elements
    • private -- considers all elements
  • --show-packages:value "exported" or "all" can be used to consider only exported packages or all packages within a module.
  • --show-module-contents:value can be used to specify the level at module declarations could be documented. A value of "api" indicates API level documentation, and "all" indicates detailed documentation.
The following options can be used to specify the elements to be documented:
  • --module documents the specified modules.
  • --expand-requires:value expand the set of modules to be documented by including some or all of the modules dependencies. The value may be one of:
    • transitive -- each module specified explicitly on the command line is expanded to include the closure of its transitive dependencies
    • all -- each module specified explicitly on the command line is expanded to include the closure of its transitive dependencies, and also all of its direct dependencies
    By default, only the specified modules will be considered, without expansion of the module dependencies.
  • packagenames can be used to specify packages.
  • -subpackages can be used to recursively load packages.
  • -exclude can be used exclude package directories.
  • sourcefilenames can be used to specify source file names.

Interactions with older options.

The new --show-* options provide a more detailed replacement for the older options -public, -protected, -package, -private. Alternatively, the older options can continue to be used as shorter forms for combinations of the new options, as described below:
Short form options mapping
Older option Equivalent to these values with the new option
--show-members --show-types --show-packages --show-module-contents
-public public public exported api
-protected protected protected exported api
-package package package all all
-private private private all all

A qualified element name is one that has its package name prepended to it, such as java.lang.String. A non-qualified name has no package name, such as String.


The following is an example doclet that displays information of a class and its members, supporting an option.
 // note imports deleted for clarity
 public class Example implements Doclet {
    Reporter reporter;
    public void init(Locale locale, Reporter reporter) {
        reporter.print(Kind.NOTE, "Doclet using locale: " + locale);
        this.reporter = reporter;

    public void printElement(DocTrees trees, Element e) {
        DocCommentTree docCommentTree = trees.getDocCommentTree(e);
        if (docCommentTree != null) {
            System.out.println("Element (" + e.getKind() + ": "
                    + e + ") has the following comments:");
            System.out.println("Entire body: " + docCommentTree.getFullBody());
            System.out.println("Block tags: " + docCommentTree.getBlockTags());

    public boolean run(DocletEnvironment docEnv) {
        reporter.print(Kind.NOTE, "overviewfile: " + overviewfile);
        // get the DocTrees utility class to access document comments
        DocTrees docTrees = docEnv.getDocTrees();

        // location of an element in the same directory as overview.html
        try {
            Element e = ElementFilter.typesIn(docEnv.getSpecifiedElements()).iterator().next();
            DocCommentTree docCommentTree
                    = docTrees.getDocCommentTree(e, overviewfile);
            if (docCommentTree != null) {
                System.out.println("Overview html: " + docCommentTree.getFullBody());
        } catch (IOException missing) {
            reporter.print(Kind.ERROR, "No overview.html found.");

        for (TypeElement t : ElementFilter.typesIn(docEnv.getIncludedElements())) {
            System.out.println(t.getKind() + ":" + t);
            for (Element e : t.getEnclosedElements()) {
                printElement(docTrees, e);
        return true;

    public String getName() {
        return "Example";

    private String overviewfile;

    public Set<? extends Option> getSupportedOptions() {
        Option[] options = {
            new Option() {
                private final List<String> someOption = Arrays.asList(

                public int getArgumentCount() {
                    return 1;

                public String getDescription() {
                    return "an option with aliases";

                public Option.Kind getKind() {
                    return Option.Kind.STANDARD;

                public List<String> getNames() {
                    return someOption;

                public String getParameters() {
                    return "file";

                public boolean process(String opt, List<String> arguments) {
                    overviewfile = arguments.get(0);
                    return true;
        return new HashSet<>(Arrays.asList(options));

    public SourceVersion getSupportedSourceVersion() {
        // support the latest release
        return SourceVersion.latest();

This doclet can be invoked with a command line, such as:

     javadoc -doclet Example \
       -overviewfile overview.html \
       -sourcepath source-location \

Migration Guide

Many of the types in the old com.sun.javadoc API do not have equivalents in this package. Instead, types in the javax.lang.model and com.sun.source APIs are used instead.

The following table gives a guide to the mapping from old types to their replacements. In some cases, there is no direct equivalent.

Guide for mapping old types to new types
Old TypeNew Type
AnnotatedType javax.lang.model.type.TypeMirror
AnnotationDesc javax.lang.model.element.AnnotationMirror
AnnotationTypeDoc javax.lang.model.element.TypeElement
AnnotationTypeElementDoc javax.lang.model.element.ExecutableElement
AnnotationValue javax.lang.model.element.AnnotationValue
ClassDoc javax.lang.model.element.TypeElement
ConstructorDoc javax.lang.model.element.ExecutableElement
Doc javax.lang.model.element.Element
DocErrorReporter jdk.javadoc.doclet.Reporter
Doclet jdk.javadoc.doclet.Doclet
ExecutableMemberDoc javax.lang.model.element.ExecutableElement
FieldDoc javax.lang.model.element.VariableElement
LanguageVersion javax.lang.model.SourceVersion
MemberDoc javax.lang.model.element.Element
MethodDoc javax.lang.model.element.ExecutableElement
PackageDoc javax.lang.model.element.PackageElement
Parameter javax.lang.model.element.VariableElement
ParameterizedType javax.lang.model.type.DeclaredType
ParamTag com.sun.source.doctree.ParamTree
ProgramElementDoc javax.lang.model.element.Element
RootDoc jdk.javadoc.doclet.DocletEnvironment
SeeTag com.sun.source.doctree.LinkTree
SerialFieldTag com.sun.source.doctree.SerialFieldTree
SourcePosition com.sun.source.util.SourcePositions
Tag com.sun.source.doctree.DocTree
ThrowsTag com.sun.source.doctree.ThrowsTree
Type javax.lang.model.type.TypeMirror
TypeVariable javax.lang.model.type.TypeVariable
WildcardType javax.lang.model.type.WildcardType
See Also:
Doclet, DocletEnvironment
  • Interface Summary
    Interface Description
    The user doclet must implement this interface, as described in the package description.
    An encapsulation of option name, aliases, parameters and descriptions as used by the Doclet.
    Represents the operating environment of a single invocation of the doclet.
    This interface provides error, warning and notice reporting.
    The interface for a custom taglet supported by doclets such as the standard doclet.
  • Class Summary
    Class Description
    This doclet generates HTML-formatted documentation for the specified modules, packages and types.
  • Enum Summary
    Enum Description
    The kind of an option.
    The mode specifying the level of detail of module documentation.
    The kind of location in which a tag may be used.