JDK-5005668 : 'Unexpected JDWP Error: 35' when evaluating 'this'
  • Type: Bug
  • Component: core-svc
  • Sub-Component: debugger
  • Affected Version: 5.0
  • Priority: P3
  • Status: Closed
  • Resolution: Duplicate
  • OS: windows_xp
  • CPU: generic
  • Submitted: 2004-03-01
  • Updated: 2004-03-02
  • Resolved: 2004-03-02
Related Reports
Duplicate :  
JDK-4918173 - JVMTI GetLocalVariableTable returns two 'this' variables for ctor
Description
The bug has been originally reported against the NetBeans IDE running on J2SE 1.5-beta b32c and 1.5-beta2 b40:
http://www.netbeans.org/issues/show_bug.cgi?id=40568

'Stepping Into' in the NetBeans debugger sometimes causes the 'Unexpected JDWP Error: 35' exception to be thrown. It turns out that it happens when the Netbeans JPDA debugger tries to evaluate 'this' object reference in the current stack frame. As a result, instance variables values cannot be inspected during debugging. It seems to be reliably reproducible with some test cases on some configurations only.

The exception stack trace starts with:

com.sun.jdi.InternalException: Unexpected JDWP
Error: 35
        at
com.sun.tools.jdi.JDWPException.toJDIException(JDWPException.java:47)
        at
com.sun.tools.jdi.StackFrameImpl.thisObject(StackFrameImpl.java:126)
        at
org.netbeans.modules.debugger.jpda.JPDACallStackFrame.getVariables(JPDACallStackFrame.java:220)

Steps to reproduce with NetBeans dev build (#200402261900):

1. Open the attached class source in the editor.
2. Place a breakpoint at line 35 -- 'Set s = ...'
3. Start the debugger via Alt-F5
4. After it stops at the breakpoint, start pressing F7 (confirm 'Step Out' / 'Don't Ask')
5. The first stack trace appears when the Name class constructor is stepped into for the first time. A series of stack traces is generated with each F7 after that.

I was not able to reproduce the behavior with JDK
1.4.2_03.

A test case and a full exception stack trace are attached.
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Comments
EVALUATION ###@###.### 2004-03-01 This looks like a case of javac bug: 4918173 GetLocalVariableTable returns two 'this' variables for ctor There were two javac bugs here: 1. javac started outputting two 'this's in the LocalVariableTable for a constructor. 2. javac was changed to not do this, but then it didn't output any 'this's for a constructur. This caused a JDWP Error 35 when one tried to access 'this' in a constructor and the .java file was compiled with -g. Jan, could you try your test again on b40 making sure that: - you compile the .java file using b40 javac (ie, don't use a .class file compiled with b39 or older javac) - compile with -g Let us know if you still get the JDWP Error 35. Thanks. You're right. The class file I used during the test was compiled using b32c. I haven't recompiled it before running it in debugger on b40. After recompiling the problem disappeared. Closing as duplicate of #4918173. ###@###.### 2004-03-02
02-03-2004