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https://issues.apache.org/jira/browse/AMQ-3369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13088678#comment-13088678
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Nigel Tamplin commented on AMQ-3369:
------------------------------------
I was also seeing this error in a high load system with embedded AMQ, but was
unable to reproduce in a small / simple test case.
The exception was originating from a single thread with a transacted session,
running in a bigger application (a subtle timing issue?).
The thread was creating TextMessages from external events, sending to a queue
then committing the session, shortly after the same thread would read back from
that queue and send to another queue then commit again.
It was the send to the 2nd queue that would very occasionally throw the
NullPointer. In 30 – 40 thousand iterations over a 12 hour period I'd see the
NullPointer maybe 20 times. I could not however contrive a test case to
reliably reproduce it.
What I could do however was to put the JVM in debug mode and catch the
NullPointer.
What I found was
public int getSize() {
if (size 0 && content null && text != null) {
size = getMinimumMessageSize();
if (marshalledProperties != null) {
size += marshalledProperties.getLength();
}
size = text.length() * 2; <<<< null pointer thrown here
}
return super.getSize();
}
Exception occurred: java.lang.NullPointerException (to be caught at:
org.apache.activemq.ActiveMQSession.send(), line=1,700 bci=447)"thread=Thread
50", org.apache.activemq.command.ActiveMQTextMessage.getSize(), line=148 bci=57
148 size = text.length() * 2;
MQ IN SMA.TEST.ORBITAL.01.CT/MQ_LOOP_BACK.1[1] list
144 size = getMinimumMessageSize();
145 if (marshalledProperties != null) {
146 size += marshalledProperties.getLength();
147 }
148 => size = text.length() * 2;
149 }
150 return super.getSize();
151 }
152
153 public String toString() {
Thread 50[1] print text
text = null
Since the check that text != null and the accessing of text it was being set to
null.
I was running version 5.3.0, and suspected the cause of the NullPointer to be
the
text = null;
assignment at the end of the beforeMarshall() method in ActiveMQTextMessage.
This looks to be the only place it could be set to null.
See
https://issues.apache.org/jira/browse/AMQ-2103
https://issues.apache.org/jira/browse/AMQ-2966
The “text = null;” assignment is present in AMQ versions 5.3.0, 5.3.1, 5.3.2,
5.4.0, 5.4.1
and removed in 5.4.2 and subsequence versions.
Unable to upgrade to 5.4.2 (or newer) in the short term, but needing to avoid
this problem immediately I rebuilt 5.3.0 removing the “text=null;” assignment
and have not experienced the NullPointerException since.
> occasionally NPE in ActiveMQTextMessage.getSize()
> -------------------------------------------------
>
> Key: AMQ-3369
> URL: https://issues.apache.org/jira/browse/AMQ-3369
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.4.1
> Environment: JDK 1.6 (64-bit), Windows Server 2008 x64
> Reporter: Ivan Pechorin
>
> Sometime we get NullPointerException when sending a text message. We use
> method send(destination, message) of interface javax.jms.MessageProducer.
> java.lang.NullPointerException
> at
> org.apache.activemq.command.ActiveMQTextMessage.getSize(ActiveMQTextMessage.java:148)
> at org.apache.activemq.ActiveMQSession.send(ActiveMQSession.java:1753)
> at
> org.apache.activemq.ActiveMQMessageProducer.send(ActiveMQMessageProducer.java:231)
> at
> org.apache.activemq.ActiveMQMessageProducerSupport.send(ActiveMQMessageProducerSupport.java:300)
> Caller code is:
> try {
> final TextMessage message = session.createTextMessage(msg);
> message.setJMSType(type);
> message.setJMSReplyTo(destination);
> message.setJMSCorrelationID(jmsMessageId);
> producer.send(destination, message);
> } catch (JMSException ex) {
> ...
> }
> I.e. we don't reuse or store the message being sent.
> We are also 100% sure that both session and its producer are used only from
> one thread at any point of time (we have custom session pool).
> Broker URI is
> vm://jboss-activemq-broker?jms.copyMessageOnSend=false&jms.objectMessageSerializationDefered=true&jms.useAsyncSend=true
> The NPE occurs occasionally, we were not able to reproduce it
> deterministically so far.
> Any suggestions on how to investigate this?
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