1 /*
   2  * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @summary Verifies the behaviour of Unsafe.fieldOffset
  27  * @library /test/lib
  28  * @modules java.base/jdk.internal.misc
  29  *          java.management
  30  * @run main FieldOffset
  31  */
  32 
  33 import java.lang.reflect.Field;
  34 import jdk.test.lib.unsafe.UnsafeHelper;
  35 import jdk.internal.misc.Unsafe;
  36 import java.lang.reflect.*;
  37 import static jdk.test.lib.Asserts.*;
  38 
  39 public class FieldOffset {
  40     public static void main(String args[]) throws Exception {
  41         Unsafe unsafe = UnsafeHelper.getUnsafe();
  42         Field[] fields = Test.class.getDeclaredFields();
  43 
  44         for (int i = 0; i < fields.length; i++) {
  45             long offset = unsafe.objectFieldOffset(fields[i]);
  46             // Ensure we got a valid offset value back
  47             assertNotEquals(offset, unsafe.INVALID_FIELD_OFFSET);
  48 
  49             // Make sure the field offset is unique
  50             for (int j = 0; j < i; j++) {
  51                 assertNotEquals(offset, unsafe.objectFieldOffset(fields[j]));
  52             }
  53         }
  54 
  55         fields = StaticTest.class.getDeclaredFields();
  56         for (int i = 0; i < fields.length; i++) {
  57             long offset = unsafe.staticFieldOffset(fields[i]);
  58             // Ensure we got a valid offset value back
  59             assertNotEquals(offset, unsafe.INVALID_FIELD_OFFSET);
  60 
  61             // Make sure the field offset is unique
  62             for (int j = 0; j < i; j++) {
  63                 assertNotEquals(offset, unsafe.staticFieldOffset(fields[j]));
  64             }
  65         }
  66 
  67     }
  68 
  69     class Test {
  70         boolean booleanField;
  71         byte byteField;
  72         char charField;
  73         double doubleField;
  74         float floatField;
  75         int intField;
  76         long longField;
  77         Object objectField;
  78         short shortField;
  79     }
  80 
  81     static class StaticTest {
  82         static boolean booleanField;
  83         static byte byteField;
  84         static char charField;
  85         static double doubleField;
  86         static float floatField;
  87         static int intField;
  88         static long longField;
  89         static Object objectField;
  90         static short shortField;
  91     }
  92 
  93 }