Open source Message Broker and Enterprise Integration Patterns provider
BSEditor: Apache ActiveMQ is the most popular and powerful open source Message Broker and Enterprise 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

Some features:
-Supports a variety of Cross Language Clients and Protocols from Java, C, C++, C#, Ruby, Perl, Python, PHP
-OpenWire for high performance clients in Java, C, C++, C#
-Stomp support so that clients can be written easily in C, Ruby, Perl, Python, PHP, ActionScript/Flash, Smalltalk to talk to ActiveMQ as well as any other popular Message Broker
-full support for the Enterprise Integration Patterns both in the JMS client and the Message Broker
-Supports many advanced features such as Message Groups, Virtual Destinations, Wildcards and Composite Destinations
-Fully supports JMS 1.1 and J2EE 1.4 with support for transient, persistent, transactional and XA messaging
-Spring Support so that ActiveMQ can be easily embedded into Spring applications and configured using Springs XML configuration mechanism

New Features in 5.2
-Additional advisory messages for messages delivered/consumed fast producers/slow consumers, Usage limits, Slaves become masters etc.
-Enhanced ssl context configuration through spring/xbean
-New individual acknowledge mode for message consumption
-Ability to configure the automatic discarding of the items being sent to the dead letter queue
-Ability to limit the maximum number of connections to a Broker
-Ability to configure separate Lock Datasource for JDBC Master slave.
activemq-camel and activemq-connection-pool now have their own modules, no longer in activemq-core
-The Default ActiveMQConnectionFactory brokerUrl now uses the failover transport.
-Uses Apache Camel 1.5. you can free download Apache ActiveMQ for Windows 5.3.0 now.