Packages 
Package Description
org.apache.activemq
The core JMS client API implementation classes.
org.apache.activemq.advisory
Support for JMS Advisory messages as well as some helper listeners to listen to the clients, producers and consumers available.
org.apache.activemq.blob
Helper classes for dealing with out-of-band BLOB objects
org.apache.activemq.broker  
org.apache.activemq.broker.region  
org.apache.activemq.broker.region.policy  
org.apache.activemq.broker.scheduler  
org.apache.activemq.command
Command objects used via the Command Pattern to communicate among nodes
org.apache.activemq.filter
Filter implementations for wildcards & JMS selectors
org.apache.activemq.filter.function
Filter Function implementations for JMS Selectors.
org.apache.activemq.jndi
JNDI support classes
org.apache.activemq.management
An implementation of the J2EE Management API
org.apache.activemq.openwire  
org.apache.activemq.openwire.v1  
org.apache.activemq.openwire.v10  
org.apache.activemq.openwire.v11  
org.apache.activemq.openwire.v12  
org.apache.activemq.openwire.v9  
org.apache.activemq.selector
JMS Selector implemetnation
org.apache.activemq.state  
org.apache.activemq.thread  
org.apache.activemq.transaction  
org.apache.activemq.transport
The core Transport abstraction and support classes
org.apache.activemq.transport.discovery
Discovery mechanism to discover brokers and clients.
org.apache.activemq.transport.discovery.masterslave
Static discovery implementation for a Master / Slave tuple
org.apache.activemq.transport.discovery.multicast
Discovery implementation using multicast
org.apache.activemq.transport.discovery.simple
Simple discovery implementation using a static list
org.apache.activemq.transport.discovery.zeroconf
A discovery agent using Zeroconf via the jmDNS library
org.apache.activemq.transport.failover
Fail-Over Transport which will automatically reconnect to a failed transport and choose one of a list of possible transport implementations to use.
org.apache.activemq.transport.fanout
Fan-out Transport implementation which ensures that a message is sent to multiple destinations such as to ensure multiple brokers received a message for non-durable topic delivery to improve redundancy
org.apache.activemq.transport.mock
A mock implementation of the Transport layer useful for testing
org.apache.activemq.transport.multicast
A Multicast based Transport implementation.
org.apache.activemq.transport.nio  
org.apache.activemq.transport.reliable
The Reliable transport deals with out of order commands as well as dealing with checking for missed commands and possibly re-requesting the replay of dropped commands.
org.apache.activemq.transport.tcp
TCP/IP based Transport implementation.
org.apache.activemq.transport.udp
UDP based Transport implementation.
org.apache.activemq.transport.ws  
org.apache.activemq.usage  
org.apache.activemq.util  
org.apache.activemq.wireformat
An API for WireFormats which are used to turn object into bytes and bytes into objects.