1 /*
   2  * Copyright (c) 2013, 2015, 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  * @bug 8021897
  27  * @summary Test getting the value for an uninitialized String object
  28  * @author Staffan Larsen
  29  *
  30  * @run build TestScaffold VMConnection TargetListener TargetAdapter
  31  * @run compile -g GetUninitializedStringValue.java
  32  * @run driver GetUninitializedStringValue
  33  */
  34 import com.sun.jdi.ReferenceType;
  35 import com.sun.jdi.StackFrame;
  36 import com.sun.jdi.StringReference;
  37 import com.sun.jdi.ThreadReference;
  38 import com.sun.jdi.event.BreakpointEvent;
  39 
  40  /********** target program **********/
  41 
  42 class GetUninitializedStringValueTarg {
  43     public static void main(String[] args) {
  44         new String("foo");
  45         System.out.println("Goodbye from GetUninitializedStringValueTarg!");
  46     }
  47 }
  48 
  49  /********** test program **********/
  50 
  51 public class GetUninitializedStringValue extends TestScaffold {
  52     ReferenceType targetClass;
  53     ThreadReference mainThread;
  54 
  55     GetUninitializedStringValue (String args[]) {
  56         super(args);
  57     }
  58 
  59     public static void main(String[] args)
  60         throws Exception
  61     {
  62         new GetUninitializedStringValue (args).startTests();
  63     }
  64 
  65     /********** test core **********/
  66 
  67     protected void runTests()
  68         throws Exception
  69     {
  70         /*
  71          * Run to String.<init>
  72          */
  73         startUp("GetUninitializedStringValueTarg");
  74         BreakpointEvent bpe = resumeTo("java.lang.String", "<init>", "(Ljava/lang/String;)V");
  75 
  76         /*
  77          * We've arrived. Look at 'this' - it will be uninitialized (the value field will not be set yet).
  78          */
  79         StackFrame frame = bpe.thread().frame(0);
  80         StringReference sr = (StringReference)frame.thisObject();
  81         if (!sr.value().equals("")) {
  82             throw new Exception("Unexpected value for the uninitialized String");
  83         }
  84 
  85         /*
  86          * resume the target listening for events
  87          */
  88         listenUntilVMDisconnect();
  89     }
  90 }