Apache ActiveMQ is an open source (Apache 2.0 licensed) message broker which fully implements the Java Message Service 1.1 (JMS). It provides "Enterprise Features" like clustering, multiple message stores, and ability to use any database as a JMS persistence provider besides VM, cache, and journal persistency. Apart from Java, ActiveMQ can be also used from .NET, C/C++ or Delphi or from scripting languages like Perl, Python, PHP and Ruby via various "Cross Language Clients" together with connecting to many protocols and platforms. These include several standard wire-level protocols, plus their own protocol called OpenWire. ActiveMQ is used in enterprise service bus implementations such as Apache ServiceMix, Apache Camel, and Mule. ActiveMQ is often used with Apache ServiceMix, Apache Camel and Apache CXF in SOA infrastructure projects.
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There are currently 3 groups being archived from ActiveMQ (activemq.apache.org).