Avoiding duplicated messages on JMS/ActiveMQ

You should look at Apache Camel, it provides an Idempotent consumer component that would work with any JMS provider, see: http://camel.apache.org/idempotent-consumer.html

Using that in combination with the ActiveMQ component makes using JMS quite simple, see: http://camel.apache.org/activemq.html

I doubt if ActiveMQ supports it natively, but it should be easy to implement an idempotent consumer. A way to do this would be to add a unique identifier to each message at the producer end, now at the consumer end using a store(db, cache etc), a check can be made to see if the message has been received before and continue to process based on that check.

I see a previous stackoverflow question along the same lines - Apache ActiveMQ 5.3 - How to configure a queue to reject duplicate messages? , that may also help.

There is now support for removing duplicate messages baked into ActiveMQ transports. See the configuration values auditDepth and auditMaximumProducerNumber in the Connection Configuration Guide.