test/java/lang/ref/EnqueueNullRef.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 * 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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 */

/* @test
 * @bug 4247236
 * @summary Ensure that reference objects with null referents can be enqueued
 */

import java.lang.ref.*;


public class EnqueueNullRef {

    static void test(ReferenceQueue q, Reference r) {
        if (!r.enqueue())
            throw new RuntimeException("Enqueue operation failed");
    }

    public static void main(String[] args) {
        ReferenceQueue q = new ReferenceQueue();
        test(q, new WeakReference(null, q));
        test(q, new SoftReference(null, q));
        test(q, new PhantomReference(null, q));
    }

}