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8259267: Refactor LoaderLeak shell test as java test.
Reviewed-by: rriggs, iignatyev, dfuchs
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Ivan Šipka authored and iignatev committed Mar 3, 2021
1 parent a118185 commit 75aa15467ec3d88a26f7c28518a24caf132818bf
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* Copyright (c) 2004, 2021, 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 5040740
* @summary annotations cause memory leak
* @library /test/lib
* @build jdk.test.lib.process.*
* @run testng LoaderLeakTest

import jdk.test.lib.Utils;
import jdk.test.lib.process.ProcessTools;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
import java.lang.annotation.Retention;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.nio.file.*;
import java.util.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

public class LoaderLeakTest {

public void testWithoutReadingAnnotations() throws Throwable {

public void testWithReadingAnnotations() throws Throwable {
runJavaProcessExpectSuccessExitCode("Main", "foo");

private void runJavaProcessExpectSuccessExitCode(String ... command) throws Throwable {
var processBuilder = ProcessTools.createJavaProcessBuilder(command)


class Main {

public static void main(String[] args) throws Exception {
for (int i = 0; i < 100; i++) {
doTest(args.length != 0);

static void doTest(boolean readAnn) throws Exception {
ClassLoader loader = new SimpleClassLoader();
var c = new WeakReference<Class<?>>(loader.loadClass("C"));
if (c.refersTo(null)) throw new AssertionError("class missing after loadClass");
// c.get() should never return null here since we hold a strong
// reference to the class loader that loaded the class referred by c.
if (c.get().getClassLoader() != loader) throw new AssertionError("wrong classloader");
if (readAnn) System.out.println(c.get().getAnnotations()[0]);
if (c.refersTo(null)) throw new AssertionError("class missing before GC");
if (c.refersTo(null)) throw new AssertionError("class missing after GC but before loader is unreachable");
loader = null;

// Might require multiple calls to System.gc() for weak-references
// processing to be complete. If the weak-reference is not cleared as
// expected we will hang here until timed out by the test harness.
while (true) {
if (c.refersTo(null)) {

@interface A {
B b();

@interface B { }

@A(b=@B()) class C { }

class SimpleClassLoader extends ClassLoader {
public SimpleClassLoader() { }

private byte[] getClassImplFromDataBase(String className) {
try {
return Files.readAllBytes(Paths.get(className + ".class"));
} catch (Exception e) {
throw new Error("could not load class " + className, e);

public Class<?> loadClass(String className, boolean resolveIt)
throws ClassNotFoundException {
switch (className) {
case "A", "B", "C" -> {
var classData = getClassImplFromDataBase(className);
return defineClass(className, classData, 0, classData.length);
return super.loadClass(className, resolveIt);


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