Enrico Musuruana created AMQ-5198:
-------------------------------------
Summary: MessageConsumer and Producer are not thread safe
Key: AMQ-5198
URL: https://issues.apache.org/jira/browse/AMQ-5198
Project: ActiveMQ
Issue Type: Bug
Affects Versions: 5.9.0
Reporter: Enrico Musuruana
We currently have an object that acts both as a consumer and as a producer over
the same queue.
Lazy initialization of the scheduler is not 100% thread safe when a consumer
and a producer are created sharing the same connection.
We encountered the following sporadic NPE when a rollback() is invoked:
Caused by: java.lang.NullPointerException
at
org.apache.activemq.thread.Scheduler.executeAfterDelay(Scheduler.java:64)
at
org.apache.activemq.ActiveMQMessageConsumer.rollback(ActiveMQMessageConsumer.java:1278)
at
org.apache.activemq.ActiveMQMessageConsumer$5.afterRollback(ActiveMQMessageConsumer.java:1054)
at
org.apache.activemq.TransactionContext.afterRollback(TransactionContext.java:157)
... 11 more
We believe that the lazy initialized getScheduler() is open for a race
condition when a publish and rollback are happening concurrently.
try {
result = scheduler = new
Scheduler("ActiveMQConnection["+info.getConnectionId().getValue()+"]
Scheduler");
scheduler.start();
} catch(Exception e) {
throw JMSExceptionSupport.create(e);
}
The suggested fix is to simply invoke the start within the constructor of the
Scheduler class.
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