test/jdk/java/nio/MappedByteBuffer/SubclassCastUOE.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 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 8191416
 * @summary Verify no UnsupportedOperationException for cast subclass
 */

import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;

public class SubclassCastUOE {
    public static void main(String[] args) throws Exception {
        ByteBuffer buf = ByteBuffer.allocateDirect(37);

        if (!(buf instanceof MappedByteBuffer)) {
            throw new RuntimeException("Direct buffer not a MappedByteBuffer");
        }

        if (((MappedByteBuffer)buf).load() != buf) {
            throw new RuntimeException("load() did not return same buffer");
        }

        if (!((MappedByteBuffer)buf).isLoaded()) {
            throw new RuntimeException("isLoaded() returned false");
        }

        if (((MappedByteBuffer)buf).force() != buf) {
            throw new RuntimeException("force() did not return same buffer");
        }
    }
}