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  *
  29  *  @author Staffan Larsen
  30  *
  31  *  @modules jdk.jdi
  32  *  @run build TestScaffold VMConnection TargetListener TargetAdapter
  33  *  @run compile -g GetUninitializedStringValue.java
  34  *  @run driver GetUninitializedStringValue
  35  */
  36 import com.sun.jdi.ReferenceType;
  37 import com.sun.jdi.StackFrame;
  38 import com.sun.jdi.StringReference;
  39 import com.sun.jdi.ThreadReference;
  40 import com.sun.jdi.event.BreakpointEvent;
  41 
  42  /********** target program **********/
  43 
  44 class GetUninitializedStringValueTarg {
  45     public static void main(String[] args) {
  46         new String("foo");
  47         System.out.println("Goodbye from GetUninitializedStringValueTarg!");
  48     }
  49 }
  50 
  51  /********** test program **********/
  52 
  53 public class GetUninitializedStringValue extends TestScaffold {
  54     ReferenceType targetClass;
  55     ThreadReference mainThread;
  56 
  57     GetUninitializedStringValue (String args[]) {
  58         super(args);
  59     }
  60 
  61     public static void main(String[] args)
  62         throws Exception
  63     {
  64         new GetUninitializedStringValue (args).startTests();
  65     }
  66 
  67     /********** test core **********/
  68 
  69     protected void runTests()
  70         throws Exception
  71     {
  72         /*
  73          * Run to String.<init>
  74          */
  75         startUp("GetUninitializedStringValueTarg");
  76         BreakpointEvent bpe = resumeTo("java.lang.String", "<init>", "(Ljava/lang/String;)V");
  77 
  78         /*
  79          * We've arrived. Look at 'this' - it will be uninitialized (the value field will not be set yet).
  80          */
  81         StackFrame frame = bpe.thread().frame(0);
  82         StringReference sr = (StringReference)frame.thisObject();
  83         if (!sr.value().equals("")) {
  84             throw new Exception("Unexpected value for the uninitialized String");
  85         }
  86 
  87         /*
  88          * resume the target listening for events
  89          */
  90         listenUntilVMDisconnect();
  91     }
  92 }