Created attachment 31041 [details]
Testcase to reproduce

Apache JMeter Version 2.10 r1533061

I was adding a Reponse Assertion element to my existing JDBC-Sampler and ran my test.
If failed with "Assertion failure message: java.lang.NullPointerException".
In the log i saw this message.

2013/11/13 10:47:33 ERROR - jmeter.threads.JMeterThread: Exception processing Assertion  java.lang.NullPointerException
	at org.apache.jmeter.assertions.ResponseAssertion.evaluateResponse(ResponseAssertion.java:337)
	at org.apache.jmeter.assertions.ResponseAssertion.getResult(ResponseAssertion.java:201)
	at org.apache.jmeter.threads.JMeterThread.processAssertion(JMeterThread.java:706)
	at org.apache.jmeter.threads.JMeterThread.checkAssertions(JMeterThread.java:677)
	at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:440)
	at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:257)
	at java.lang.Thread.run(Thread.java:662)


Only with debugging JMeter i found out, that i had a typo in the "JMeter Variable" parameter.

See the attached testcase to reproduce the exception.

I would expect an errormessage, that tells me exactly what is wrong.
e.g. "variable x not found in current scope"