jdk-24/test/jdk/java/util/logging/ClassLoaderLeakTest.java

/*
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 * 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.
 *
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 * questions.
 */

/**
 * @test
 * @bug     6799583
 *
 * @summary Test verifes that LogManager shutdown hook does not cause
 *          an application classloader leaks.
 *
 * @run     main/othervm ClassLoaderLeakTest
 */

import java.io.File;
import java.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.concurrent.CountDownLatch;
import java.util.logging.Logger;

public class ClassLoaderLeakTest {

    private static CountDownLatch doneSignal;
    private static CountDownLatch launchSignal;
    private static ThreadGroup appsThreadGroup;
    private static Throwable launchFailure = null;

    public static void main(String[] args) {
        appsThreadGroup = new ThreadGroup("MyAppsThreadGroup");
        doneSignal = new CountDownLatch(1);
        launchSignal = new CountDownLatch(1);

        Runnable launcher = new Runnable() {
            public void run() {
                try {
                    ClassLoader cl =
                        Thread.currentThread().getContextClassLoader();
                    Class<?> appMain = cl.loadClass("AppTest");
                    Method launch =
                        appMain.getDeclaredMethod("launch", doneSignal.getClass());

                    Constructor<?> c = appMain.getConstructor();

                    Object o = c.newInstance();

                    launch.invoke(o, doneSignal);

                } catch (Throwable e) {
                    launchFailure = e;
                } finally {
                    launchSignal.countDown();
                }
            }
        };

        /* prepare test  class loader */
        URL pwd = null;
        try {
            pwd = new File(System.getProperty("test.classes",".")).toURI().toURL();
        } catch (MalformedURLException e) {
            throw new RuntimeException("Test failed.", e);
        }
        URL[] urls = new URL[] { pwd };

         MyClassLoader appClassLoader = new MyClassLoader(urls, "test0");
         WeakReference<MyClassLoader> ref =
                 new WeakReference<>(appClassLoader);


         Thread appThread = new Thread(appsThreadGroup, launcher, "AppThread-0");
         appThread.setContextClassLoader(appClassLoader);

         appThread.start();
         appClassLoader = null;
         launcher = null;
         appThread = null;

         /* wait for laucnh completion */
         try {
             launchSignal.await();
         } catch (InterruptedException e) {
         }

         /* check if launch failed */
         if (launchFailure != null) {
             throw new RuntimeException("Test failed.", launchFailure);
         }

         /* wait for test app excution completion */
         try {
             doneSignal.await();
         } catch (InterruptedException e) {
         }

         /* give a chence to GC */
         waitAndGC(5);

         if (ref.get() != null) {
             throw new RuntimeException("Test failed: classloader is still alive");
         }

         System.out.println("Test passed.");
    }

    private static class MyClassLoader extends URLClassLoader {

        private static boolean verbose =
            Boolean.getBoolean("verboseClassLoading");
        private String uniqClassName;

        public MyClassLoader(URL[] urls, String uniq) {
            super(urls);

            uniqClassName = uniq;
        }

        public Class<?> loadClass(String name) throws ClassNotFoundException {
            if (verbose) {
                System.out.printf("%s: load class %s\n", uniqClassName, name);
            }
            if (uniqClassName.equals(name)) {
                return Object.class;
            }
            return super.loadClass(name);
        }

        public String toString() {
            return "MyClassLoader(" + uniqClassName + ")";
        }
    }

    private static void waitAndGC(int sec) {
        int cnt = sec;
        System.out.print("Wait ");
        while (cnt-- > 0) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
            // do GC every 3 seconds
            if (cnt % 3 == 2) {
                System.gc();
                System.out.print("+");
            } else {
                System.out.print(".");
            }
            //checkErrors();
        }
        System.out.println("");
    }
}


class AppTest {
    public AppTest() {

    }

    public void launch(CountDownLatch done) {
        Logger log = Logger.getLogger("app_test_logger");
        log.fine("Test app is launched");

        done.countDown();
    }
}