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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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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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package jdk.jfr.jvm;

import java.io.ByteArrayOutputStream;

import java.io.InputStream;

import jdk.jfr.Event;

import jdk.jfr.FlightRecorder;

import jdk.jfr.internal.JVM;

/**

 * @test

 * @key jfr

 * @summary Unit test for JVM#getUnloadedEventClassCount

 * @requires vm.hasJFR

 *

 * @library /test/lib

 * @modules jdk.jfr/jdk.jfr.internal

 *          java.base/jdk.internal.misc

 *

 * @run main/othervm -Xlog:class+unload -Xlog:gc -Xmx16m jdk.jfr.jvm.TestUnloadEventClassCount

 */

public class TestUnloadEventClassCount {

    private static final String EVENT_NAME = "jdk.jfr.jvm.TestUnloadEventClassCount$ToBeUnloaded";

    public static class ToBeUnloaded extends Event {

    }

    static public class MyClassLoader extends ClassLoader {

        public MyClassLoader() {

            super("MyClassLoader", null);

        }

        public final Class<?> defineClass(String name, byte[] b) {

            return super.defineClass(name, b, 0, b.length);

        }

    }

    public static MyClassLoader myClassLoader;

    public static void main(String[] args) throws Throwable {

        FlightRecorder.getFlightRecorder();

        myClassLoader = createClassLoaderWithEventClass();

        System.out.println("MyClassLoader instance created");

        long initialCount = JVM.getJVM().getUnloadedEventClassCount();

        System.out.println("Initiali unloaded count is " + initialCount);

        myClassLoader = null;

        System.out.println("Reference to class loader cleared");

        long count = 0;

        do {

            System.gc();

            System.out.println("GC triggered");

            count = JVM.getJVM().getUnloadedEventClassCount();

            System.out.println("Unloaded count was " + count);

            Thread.sleep(1000); // sleep to reduce log

        } while (count != initialCount + 1);

    }

    private static MyClassLoader createClassLoaderWithEventClass() throws Exception {

        String resourceName = EVENT_NAME.replace('.', '/') + ".class";

        try (InputStream is = TestUnloadEventClassCount.class.getClassLoader().getResourceAsStream(resourceName)) {

            ByteArrayOutputStream baos = new ByteArrayOutputStream();

            byte[] buffer = new byte[4096];

            int byteValue = 0;

            while ((byteValue = is.read(buffer, 0, buffer.length)) != -1) {

                baos.write(buffer, 0, byteValue);

            }

            baos.flush();

            MyClassLoader myClassLoader = new MyClassLoader();

            Class<?> eventClass = myClassLoader.defineClass(EVENT_NAME, baos.toByteArray());

            if (eventClass == null) {

                throw new Exception("Could not define test class");

            }

            if (eventClass.getSuperclass() != Event.class) {

                throw new Exception("Superclass should be jdk.jfr.Event");

            }

            if (eventClass.getSuperclass().getClassLoader() != null) {

                throw new Exception("Class loader of jdk.jfr.Event should be null");

            }

            if (eventClass.getClassLoader() != myClassLoader) {

                throw new Exception("Incorrect class loader for event class");

            }

            eventClass.newInstance(); // force <clinit>

            return myClassLoader;

        }

    }

}