FULL PRODUCT VERSION :
java version "1.6.0_02"
Java(TM) SE Runtime Environment (build 1.6.0_02-b06)
Java HotSpot(TM) Client VM (build 1.6.0_02-b06, mixed mode, sharing)

FULL OS VERSION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Nothing applicable.

A DESCRIPTION OF THE PROBLEM :
While testing my application (built with Eclipse v3.3 (Europa SDK), I suddenly received a report of an "unexpected error" detected by the JRE (EXCEPTION_ACCESS_VIOLATION (0xc0000005).

After some experimentation I was able to track down the problem to a line of code making use of the StringBuilder class. The code was attempting to build a string using an object whose value happened to be 'null'. Rather than submitting the entire application I have reduced the problem to a few lines of code which always reproduces the problem, and which are included in the "Steps to Reproduce" area.

THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: Did not try

THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Did not try

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
<code>
1 public class StringBuilderTest {
2 public static void main(String[] args) {
3 String padding = "\t", owner = null;
4 StringBuilder entity = new StringBuilder();
5 entity.append(padding + "owner: " + owner==null?"none":owner.toString() + "\n");
6 System.out.println(entity.toString());
7 }
8 }
</code>

Steps to reproduce the problem in Eclipse:
1. Place a breakpoint at line 5
2. Begin execution
3. Use F5 to repeatedly single-step through the StringBuilder operations until the exception occurs, in class String.class, somewhere between lines 203 and 217 (a String constructor).




EXPECTED VERSUS ACTUAL BEHAVIOR :
The expected output from the above code would be the string:
\towner: null\n

The actual result varies between an unexpected exception report and an unhandled exception (when running through the debugger the unexpected exception occurs always)


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Attached seperatly

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class StringBuilderTest {
    public static void main(String[] args) {
        String padding = "\t", owner = null;
        StringBuilder entity = new StringBuilder();
        entity.append(padding + "owner: " + owner==null?"none":owner.toString() + "\n");
        System.out.println(entity.toString());
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Wrap the "?:" condition in parentheses.