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13  * accompanied this code).
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23 
24 /*
25  * @test
26  * @bug 6822627
27  * @summary Test that ReferenceType.constantPool does not produce an NPE
28  * @author Egor Ushakov
29  *
30  * @modules jdk.jdi/com.sun.tools.jdi:+open
31  *
32  * @run build TestScaffold VMConnection
33  * @run compile -g ConstantPoolInfoGC.java
34  * @run main/othervm ConstantPoolInfoGC
35  */
36 
37 import com.sun.jdi.ReferenceType;
38 import com.sun.tools.jdi.ReferenceTypeImpl;
39 
40 import java.lang.ref.Reference;
41 import java.lang.reflect.Field;
42 import java.util.Arrays;
43 
44     /********** target program **********/
45 
46 class ConstantPoolGCTarg {
main(String[] args)47     public static void main(String[] args){
48         System.out.println("Anything");
49     }
50 }
51 
52     /********** test program **********/
53 
54 public class ConstantPoolInfoGC extends TestScaffold {
55     ReferenceType targetClass;
56 
ConstantPoolInfoGC(String args[])57     ConstantPoolInfoGC(String args[]) {
58         super(args);
59     }
60 
main(String[] args)61     public static void main(String[] args)      throws Exception {
62         new ConstantPoolInfoGC(args).startTests();
63     }
64 
65     /********** test core **********/
66 
runTests()67     protected void runTests() throws Exception {
68         targetClass = startToMain("ConstantPoolGCTarg").location().declaringType();
69 
70         if (vm().canGetConstantPool()) {
71             byte[] cpbytes = targetClass.constantPool();
72 
73             // imitate SoftReference cleared
74             Field constantPoolBytesRef = ReferenceTypeImpl.class.getDeclaredField("constantPoolBytesRef");
75             constantPoolBytesRef.setAccessible(true);
76             Reference softRef = (Reference) constantPoolBytesRef.get(targetClass);
77             softRef.clear();
78 
79             byte[] cpbytes2 = targetClass.constantPool();
80             if (!Arrays.equals(cpbytes, cpbytes2)) {
81                 failure("Consequent constantPool results vary, first was : " + cpbytes + ", now: " + cpbytes2);
82             };
83 
84         } else {
85             System.out.println("can get constant pool version not supported");
86         }
87 
88 
89         /*
90          * resume until end
91          */
92         listenUntilVMDisconnect();
93 
94         /*
95          * deal with results of test
96          * if anything has called failure("foo") testFailed will be true
97          */
98         if (!testFailed) {
99             println("ConstantPoolInfoGC: passed");
100         } else {
101             throw new Exception("ConstantPoolInfoGC: failed");
102         }
103     }
104 }
105