jdk-24/hotspot/test/runtime/Unsafe/AllocateInstance.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
 * @summary Verifies the behaviour of Unsafe.allocateInstance
 * @library /testlibrary
 * @modules java.base/sun.misc
 *          java.management
 * @run main AllocateInstance
 */

import com.oracle.java.testlibrary.*;
import sun.misc.Unsafe;
import static com.oracle.java.testlibrary.Asserts.*;

public class AllocateInstance {
    public static void main(String args[]) throws Exception {
        Unsafe unsafe = Utils.getUnsafe();

        // allocateInstance() should not result in a call to the constructor
        TestClass tc = (TestClass)unsafe.allocateInstance(TestClass.class);
        assertFalse(tc.calledConstructor);

        // allocateInstance() on an abstract class should result in an InstantiationException
        try {
            AbstractClass ac = (AbstractClass)unsafe.allocateInstance(AbstractClass.class);
            throw new RuntimeException("Did not get expected InstantiationException");
        } catch (InstantiationException e) {
            // Expected
        }
    }

    class TestClass {
        public boolean calledConstructor = false;

        public TestClass() {
            calledConstructor = true;
        }
    }

    abstract class AbstractClass {
        public AbstractClass() {}
    }
}