/*

 * Copyright (c) 2013, 2016, 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

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 */

/*

 * @test UnloadTest

 * @modules java.base/jdk.internal.misc

 * @library /runtime/testlibrary /test/lib

 * @library classes

 * @build sun.hotspot.WhiteBox test.Empty

 * @run main ClassFileInstaller sun.hotspot.WhiteBox

 *                              sun.hotspot.WhiteBox$WhiteBoxPermission

 * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI UnloadTest

 */

import sun.hotspot.WhiteBox;

/**

 * Test that verifies that classes are unloaded when they are no longer reachable.

 *

 * The test creates a class loader, uses the loader to load a class and creates an instance

 * of that class. The it nulls out all the references to the instance, class and class loader

 * and tries to trigger class unloading. Then it verifies that the class is no longer

 * loaded by the VM.

 */

public class UnloadTest {

    private static String className = "test.Empty";

    public static void main(String... args) throws Exception {

       run();

    }

    private static void run() throws Exception {

        final WhiteBox wb = WhiteBox.getWhiteBox();

        ClassUnloadCommon.failIf(wb.isClassAlive(className), "is not expected to be alive yet");

        ClassLoader cl = ClassUnloadCommon.newClassLoader();

        Class<?> c = cl.loadClass(className);

        Object o = c.newInstance();

        ClassUnloadCommon.failIf(!wb.isClassAlive(className), "should be live here");

        cl = null; c = null; o = null;

        ClassUnloadCommon.triggerUnloading();

        ClassUnloadCommon.failIf(wb.isClassAlive(className), "should have been unloaded");

    }

}