Released in 2004, ActiveMQ is the open source MOM published by the Apache Foundation.
ActiveMQ relies on a handful of other Apache projects: Apache Camel (partial implementation of enterprise integration patterns) and Jetty (Java application server integrated with ActiveMQ). ActiveMQ in turn is used by several other major projects: Apache Service Mix, Mule and Geronimo (as the default JMS provider). ActiveMQ’s message processing is undoubtedly its most famous asset, after its superior connectivity. Thanks to the integrated Camel project, it can process messages according to enterprise integration patterns (EIPs).
ActiveMQ is developed in Java. The diversity of languages and environments it supports is particularly impressive and is one of ActiveMQ’s greatest assets. The languages by which ActiveMQ can be accessed are: C, C++, Ajax, RESTful and SOAP, .NET, Delphi, FreePascal, Perl, PHP, Pike, Python, Ruby, etc.
It is distributed under the Apache License 2.0.