test/hotspot/jtreg/runtime/Unsafe/GetPutObject.java

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/*
 * @test
 * @summary Verify behaviour of Unsafe.get/putObject
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 *          java.management
 * @run main GetPutObject
 */

import java.lang.reflect.Field;
import jdk.internal.misc.Unsafe;
import static jdk.test.lib.Asserts.*;

public class GetPutObject {
    public static void main(String args[]) throws Exception {
        Unsafe unsafe = Unsafe.getUnsafe();
        Test t = new Test();
        Object o = new Object();
        Field field = Test.class.getField("o");

        long offset = unsafe.objectFieldOffset(field);
        assertEquals(t.o, unsafe.getReference(t, offset));

        unsafe.putReference(t, offset, o);
        assertEquals(o, unsafe.getReference(t, offset));

        Object arrayObject[] = { unsafe, null, new Object() };
        int scale = unsafe.arrayIndexScale(arrayObject.getClass());
        offset = unsafe.arrayBaseOffset(arrayObject.getClass());
        for (int i = 0; i < arrayObject.length; i++) {
            assertEquals(unsafe.getReference(arrayObject, offset), arrayObject[i]);
            offset += scale;
        }
    }

    static class Test {
        public Object o = new Object();
    }
}