Null pointer exception on stop Threads command (Run>Stop)

[asfimport]

stef (Bug 49734):
Some times when asking jmeter to stop a running thread group a null pointer exception is thrown and the window saying "Stopping Threads" remains displayed.
The exception is:
Exception in thread "Thread-357" java.lang.NullPointerException
at org.apache.jmeter.engine.StandardJMeterEngine.tellThreadsToStop(StandardJMeterEngine.java:542)
at org.apache.jmeter.engine.StandardJMeterEngine.access$700(StandardJMeterEngine.java:57)
at org.apache.jmeter.engine.StandardJMeterEngine$StopTest.run(StandardJMeterEngine.java:357)
at java.lang.Thread.run(Unknown Source)

It seams a null check on the Thread object retreived should be done in this method:

private void tellThreadsToStop() {
    synchronized (allThreads) { // Protect iterator
        Iterator<JMeterThread> iter = new HashSet<JMeterThread>(allThreads.keySet()).iterator();
        while (iter.hasNext()) {
            JMeterThread item = iter.next();
            item.stop(); // set stop flag
            item.interrupt(); // interrupt sampler if possible
            Thread t = allThreads.get(item);
            t.interrupt(); // also interrupt JVM thread           // <-- Line 542
        }
    }
}

Regards,

Stephane

Severity: major
OS: Windows XP

[asfimport]

Sebb (migrated from Bugzilla):
Thanks for the report; fixed in SVN:

URL: http://svn.apache.org/viewvc?rev=986020&view=rev
Log:
#2391 - Null pointer exception on stop Threads command (Run>Stop)

Modified:
jakarta/jmeter/trunk/src/core/org/apache/jmeter/engine/StandardJMeterEngine.java
jakarta/jmeter/trunk/xdocs/changes.xml

[asfimport]

Cheng Chi (migrated from Bugzilla):
(In reply to comment 1)

Thanks for the report; fixed in SVN:

URL: http://svn.apache.org/viewvc?rev=986020&view=rev
Log:
#2391 - Null pointer exception on stop Threads command (Run>Stop)

Modified:

jakarta/jmeter/trunk/src/core/org/apache/jmeter/engine/StandardJMeterEngine.java
jakarta/jmeter/trunk/xdocs/changes.xml

Hi, Sebb,

The Fix is confused, can you explain why t can be 'null' here or shall we need to dig the root cause deeper? :)

if (t != null ) { // #2391
t.interrupt(); // also interrupt JVM thread
}

Thanks!
Cheng Chi

[asfimport]

Sebb (migrated from Bugzilla):
See the original bug report stack trace.