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8308715: Create a mechanism for Implicitly Declared Class javadoc
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Reviewed-by: jjg
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pavelrappo committed Dec 5, 2023
1 parent c8fa758 commit 430564c
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Showing 5 changed files with 238 additions and 7 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -423,4 +423,10 @@ public boolean accessInternalAPI() {
return Map.of();

* If a similar query is ever added to javax.lang.model, use that instead.
public static boolean isImplicitlyDeclaredClass(Element e) {
return e instanceof ClassSymbol c && c.isImplicit();
Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,8 @@ public Void scan(DocCommentTree tree, TreePath p) {
if (isNormalClass(p.getParentPath())) {
} else if (!isOverridingMethod && !isSynthetic() && !isAnonymous() && !isRecordComponentOrField()) {
} else if (!isOverridingMethod && !isSynthetic() && !isAnonymous() && !isRecordComponentOrField()
&& !isImplicitlyDeclaredClass(env.currPath.getLeaf())) {
return null;
Expand Down Expand Up @@ -1275,11 +1276,20 @@ private boolean isRecordComponentOrField() {
private boolean isNormalClass(TreePath p) {
return switch (p.getLeaf().getKind()) {
case ENUM, RECORD -> false;
case CLASS -> true;
case CLASS -> !isImplicitlyDeclaredClass(p.getLeaf());
default -> throw new IllegalArgumentException(p.getLeaf().getKind().name());

* If a similar query is ever added to com.sun.source.tree, use that instead.
private boolean isImplicitlyDeclaredClass(Tree t) {
return t.getKind() == Tree.Kind.CLASS
&& t instanceof classDecl
&& (classDecl.mods.flags & != 0;

void markEnclosingTag(Flag flag) {
TagStackItem top = tagStack.peek();
if (top != null)
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@
import jdk.javadoc.doclet.DocletEnvironment;
import jdk.javadoc.doclet.DocletEnvironment.ModuleMode;
import jdk.javadoc.internal.doclets.toolkit.WorkArounds;

import static;

Expand Down Expand Up @@ -993,7 +994,7 @@ public boolean isSelected(Element e) {
visibleElementVisitor = new SimpleElementVisitor14<>() {
public Boolean visitType(TypeElement e, Void p) {
if (!accessFilter.checkModifier(e)) {
if (!accessFilter.checkModifier(e) && !WorkArounds.isImplicitlyDeclaredClass(e)) {
return false; // it is not allowed
Element encl = e.getEnclosingElement();
Expand All @@ -1012,7 +1013,13 @@ public Boolean visitType(TypeElement e, Void p) {

protected Boolean defaultAction(Element e, Void p) {
return accessFilter.checkModifier(e);
if (accessFilter.checkModifier(e)) {
return true;
} else {
return WorkArounds.isImplicitlyDeclaredClass(e.getEnclosingElement())
&& e.getKind() != ElementKind.CONSTRUCTOR /* nothing interesting in that ctor */
&& AccessLevel.of(e.getModifiers()).compareTo(AccessLevel.PACKAGE) >= 0;

Expand Down
15 changes: 12 additions & 3 deletions src/jdk.javadoc/share/man/javadoc.1
Original file line number Diff line number Diff line change
Expand Up @@ -84,9 +84,9 @@ options, package names, and source file names in any order.
The \f[V]javadoc\f[R] tool parses the declarations and documentation
comments in a set of Java source files and produces corresponding HTML
pages that describe (by default) the public and protected classes,
nested and unnamed classes (but not anonymous inner classes),
interfaces, constructors, methods, and fields.
You can use the\f[V]javadoc\f[R] tool to generate the API documentation
nested and implicitly declared classes (but not anonymous inner
classes), interfaces, constructors, methods, and fields.
You can use the \f[V]javadoc\f[R] tool to generate the API documentation
or the implementation documentation for a set of source files.
You can run the \f[V]javadoc\f[R] tool on entire packages, individual
Expand Down Expand Up @@ -421,6 +421,15 @@ Prints version information.
Reports an error if any warnings occur.
Note that if a Java source file contains an implicitly declared class,
then that class and its public, protected, and package members will be
documented regardless of the options such as \f[V]--show-types\f[R],
\f[V]--show-members\f[R], \f[V]-private\f[R], \f[V]-protected\f[R],
\f[V]-package\f[R], and \f[V]-public\f[R].
If \f[V]--show-members\f[R] is specified with value \f[V]private\f[R] or
if \f[V]-private\f[R] is used then all private members of an implicitly
declared class will be documented too.
.SS Extra \f[V]javadoc\f[R] Options
\f[I]Note:\f[R] The additional options for \f[V]javadoc\f[R] are subject
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Original file line number Diff line number Diff line change
@@ -0,0 +1,199 @@
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit if you need additional information or have any
* questions.

* @test
* @bug 8308715
* @library /tools/lib ../../lib
* @modules jdk.compiler/
* jdk.compiler/
* jdk.javadoc/jdk.javadoc.internal.tool
* @build javadoc.tester.* toolbox.ToolBox toolbox.ModuleBuilder builder.ClassBuilder
* @run main/othervm TestImplicitlyDeclaredClasses

import java.nio.file.Path;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.regex.Pattern;

import javadoc.tester.JavadocTester;
import toolbox.ToolBox;

public class TestImplicitlyDeclaredClasses extends JavadocTester {

private final ToolBox tb = new ToolBox();

public static void main(String... args) throws Exception {
new TestImplicitlyDeclaredClasses().runTests();

public void test(Path base) throws IOException {
int i = 0;
for (Method main : mainMethods())
for (Method otherMethod : otherMethods()) {
var methods = List.of(main, otherMethod);
var index = String.valueOf(i++);
var src = base.resolve(Path.of("src-" + index, ""));
// TODO: remove preview-related options once "Implicitly Declared
// Classes and Instance Main Methods" has been standardized
javadoc("--enable-preview", "--source=22",
"-d", base.resolve("out-" + index).toString(),

// there must be no warning on undocumented (default) constructor
checkOutput(Output.OUT, false, """
warning: use of default constructor, which does not provide a comment""");
// the (default) constructor must neither be linked nor mentioned
checkOutput("MyClass.html", false, "%3Cinit%3E");
checkOutput("MyClass.html", false, "Constructor");
// a method that is public, protected or declared with package
// access must either be documented or, if it doesn't have a
// comment, must be warned about
int nWarnedMethods = 0;
for (var m : methods) {
if (m.accessModifier.compareTo(Access.PACKAGE) >= 0) {
if (m.comment.isEmpty()) {
checkOutput(Output.OUT, true, "warning: no comment\n" + m);
} else {
checkOutput("MyClass.html", true,
<span class="return-type">%s</span>"""
<span class="element-name">%s</span>"""
// there must be no warning on uncommented implicitly declared class
// Here's a non-obvious part. A warning message for an uncommented
// class is the same as that of a method. Moreover, since the class
// is implicit, its AST position is that of the first method.
// Put differently, if the class is uncommented, the warning about
// it is indistinguishable from that of the first method, if that
// method is uncommented.
// Here's how this check works: if an undocumented class warning
// is present, then the total count of undocumented element warnings
// is one greater than that of undocumented methods.
// Of course, it's possible, although seemingly unlikely, that
// this check passes, when it should fail: the warning for class
// is generated, but the warning for the first method is not.
// Numbers are equal, test passes.
checking("uncommented class warning");
long all = Pattern.compile("warning: no comment")
if (all != nWarnedMethods) {
failed("%d/%d".formatted(all, nWarnedMethods));
} else {

private Iterable<Method> mainMethods() {
return generate(
List.of("/** main comment */", ""),
// adding PRIVATE will increase test output size and run time
EnumSet.of(Access.PUBLIC, Access.PROTECTED, Access.PACKAGE),
// adding final will increase test output size and run time
List.of("static", ""),
List.of("String[] args", "")

private Iterable<Method> otherMethods() {
return generate(
List.of("/** other comment */", ""),
// adding PROTECTED or PUBLIC will increase test output size and run time
EnumSet.of(Access.PACKAGE, Access.PRIVATE),
// adding final or static will increase test output size and run time

private Iterable<Method> generate(Iterable<String> comments,
Iterable<Access> accessModifiers,
Iterable<String> otherModifiers,
Iterable<String> returnValues,
String name,
Iterable<String> args) {
var methods = new ArrayList<Method>();
for (var comment : comments)
for (var accessModifier : accessModifiers)
for (var otherModifier : otherModifiers)
for (var returnValue : returnValues)
for (var arg : args)
methods.add(new Method(comment, accessModifier,
otherModifier, returnValue, name, arg));
return methods;


record Method(String comment,
Access accessModifier,
String otherModifier,
String returnValue,
String name,
String arg) {

public String toString() {
return Stream.of(comment, access(accessModifier), otherModifier,
returnValue, name + "(" + arg + ") { }")
.filter(s -> !s.isEmpty())
.collect(Collectors.joining(" "));

private static String access(Access accessModifier) {
return switch (accessModifier) {
case PRIVATE -> "private";
case PACKAGE -> "";
case PROTECTED -> "protected";
case PUBLIC -> "public";

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