1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 import java.lang.reflect.Field;
18 import jdk.internal.misc.Unsafe;
19 
20 public class Main {
assertLongEquals(long expected, long result)21   private static void assertLongEquals(long expected, long result) {
22     if (expected != result) {
23       throw new Error("Expected: " + expected + ", found: " + result);
24     }
25   }
26 
getUnsafe()27   private static Unsafe getUnsafe() throws Exception {
28     Class<?> unsafeClass = Class.forName("jdk.internal.misc.Unsafe");
29     Field f = unsafeClass.getDeclaredField("theUnsafe");
30     f.setAccessible(true);
31     return (Unsafe) f.get(null);
32   }
33 
main(String[] args)34   public static void main(String[] args) throws Exception {
35     Unsafe unsafe = getUnsafe();
36 
37     testUnsafeGetLong(unsafe);
38   }
39 
testUnsafeGetLong(Unsafe unsafe)40   public static void testUnsafeGetLong(Unsafe unsafe) throws Exception {
41     TestClass test = new TestClass();
42     Field longField = TestClass.class.getDeclaredField("longVar");
43     long lvar = unsafe.objectFieldOffset(longField);
44     lvar = unsafe.getLong(test, lvar);
45     assertLongEquals(1122334455667788L, lvar);
46   }
47 
48   private static class TestClass {
49     public long longVar = 1122334455667788L;
50   }
51 }
52