diff --git a/src/java.compiler/share/classes/javax/lang/model/util/Elements.java b/src/java.compiler/share/classes/javax/lang/model/util/Elements.java index 7f0b493572e0d..5d97674c53d56 100644 --- a/src/java.compiler/share/classes/javax/lang/model/util/Elements.java +++ b/src/java.compiler/share/classes/javax/lang/model/util/Elements.java @@ -1,5 +1,5 @@ /* - * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -778,6 +778,12 @@ default TypeElement getOutermostTypeElement(Element e) { * elements.getTypeElement("I")); * } * + * @apiNote This method examines the method's name, signature, subclass relationship, and accessibility + * in determining whether one method overrides another, as specified in JLS {@jls 8.4.8.1}. + * In addition, an implementation may have stricter checks including method modifiers, return types and + * exception types as described in JLS {@jls 8.4.8.1} and {@jls 8.4.8.3}. + * Note that such additional compile-time checks are not guaranteed and may vary between implementations. + * * @param overrider the first method, possible overrider * @param overridden the second method, possibly being overridden * @param type the class or interface of which the first method is a member diff --git a/test/langtools/tools/javac/processing/model/util/elements/overrides/S.java b/test/langtools/tools/javac/processing/model/util/elements/overrides/S.java new file mode 100644 index 0000000000000..f6da3324acb33 --- /dev/null +++ b/test/langtools/tools/javac/processing/model/util/elements/overrides/S.java @@ -0,0 +1,63 @@ +/* + * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * 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 www.oracle.com if you need additional information or have any + * questions. + */ + +/* + * This file models a few cases where Elements.overrides produces a false + * positive which warrants @apiNote. + */ + +// S.java does not compile because it violates the JLS rules for overrides +class S { + + public void m() { } +} + +// `protected` is a weaker modifier than `public` +class T1 extends S { + + protected void m() { } +} + +// `package-private` is a weaker modifier than `public` +class T2 extends S { + + void m() { } +} + +// `private` methods cannot override public method +class T3 extends S { + + private void m() { } +} + +// return type int is not compatible with void +class T4 extends S { + + public int m() { return 0; } +} + +// adding a checked exception violates the override rule +class T5 extends S { + + public void m() throws Exception { } +} diff --git a/test/langtools/tools/javac/processing/model/util/elements/overrides/TestOverrides.java b/test/langtools/tools/javac/processing/model/util/elements/overrides/TestOverrides.java new file mode 100644 index 0000000000000..724dda1d4820d --- /dev/null +++ b/test/langtools/tools/javac/processing/model/util/elements/overrides/TestOverrides.java @@ -0,0 +1,64 @@ +/* + * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * 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 www.oracle.com if you need additional information or have any + * questions. + */ + +/* + * @test + * @bug 8174840 + * @library /tools/javac/lib + * @build JavacTestingAbstractProcessor TestOverrides + * @compile -processor TestOverrides -proc:only S.java + */ + +import java.util.Set; +import javax.annotation.processing.RoundEnvironment; +import javax.lang.model.element.ExecutableElement; +import javax.lang.model.element.TypeElement; + +import static javax.lang.model.element.ElementKind.METHOD; + +public class TestOverrides extends JavacTestingAbstractProcessor { + + @Override + public boolean process(Set annotations, RoundEnvironment round) { + if (!round.processingOver()) { + var sm = mIn(elements.getTypeElement("S")); + for (var subtypeName : new String[]{"T1", "T2", "T3", "T4", "T5"}) { + var t = elements.getTypeElement(subtypeName); + var tm = mIn(t); + if (!elements.overrides(tm, sm, t)) + messager.printError(String.format( + "%s does not override from %s method %s", tm, t.getQualifiedName(), sm)); + } + } + return true; + } + + private ExecutableElement mIn(TypeElement t) { + return t.getEnclosedElements().stream() + .filter(e -> e.getKind() == METHOD) + .filter(e -> e.getSimpleName().toString().equals("m")) + .map(e -> (ExecutableElement) e) + .findAny() + .get(); + } +}