Apache ActiveMQ is the most popular and powerful open source messaging and
Integration Patterns provider.

Apache ActiveMQ is fast, supports many Cross Language Clients and Protocols,
comes with easy to use Enterprise Integration Patterns and many advanced
features while fully supporting JMS 1.1 and J2EE 1.4. Apache ActiveMQ is
released under the Apache 2.0 License.

This package provides an /etc/rc.d/rc.activemq init script to manage the main
ActiveMQ system instance. If you want to run different instances on the same
machine:
1) create the configuration file /etc/default/activemq-instance-<INSTANCENAME>
2) create an appropriate ACTIVEMQ_HOME
3) ln -sf /usr/share/activemq/bin/activemq /usr/local/bin/activemq-instance-<INSTANCENAME>
4) use /usr/local/bin/activemq-instance-<INSTANCENAME> to start/stop/restart
your own instance.