ActiveMQ is designed to support mutliple different topologies and protocols. Which one you use depends on your messaging requirements, quality of service and network topology.

The following table describes the different network protocols available along with showing the connection URL string you use to enable this communication protocol. You can specify the connection URL on an ActiveMQConnectionFactory (in a constructor or via the brokerURL property).

e.g. if you don't want to bother setting up JNDI and so forth and just wanna create a JMS connection you can do something like

ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://somehost:61616");
Connection connection = factory.createConnection();

Protocol Summary

Protocol Example Description Server?
VM vm://host:port Client connect to each other within the same JVM. This does use an asynchronous channel and a separate worker thread. You can enable sync sending using a query parameter, such as
vm://localhost?async=false
Yes
TCP tcp://host:port Client connects to the broker at the given URL Yes
SSL ssl://host:port Client connects to the broker at the given URL Yes
List list:Uri1,Uri2,Uri3,...,UriN Provides a list of possible URIs to connect to and one is randomly chosen. If the connection fails then the JMS connection fails  
Reliable reliable:Uri1,Uri2,Uri3,...,UriN Provides a list of possible URIs to connect to and one is randomly chosen. If the connection fails then the transport auto-reconnects to a different one  
Peer peer://serviceName Creates a pure peer to peer network of nodes of a given service name. In peer mode there is no server, nodes just automatically connect and make a peer network. The serviceName allows you to keep networks apart from each other, such as development, testing, UAT and production.  
Discovery discovery://host:port Uses Discovery to connect to an available broker of the correct channel name. If multiple brokers can be found then one is chosen at random. If the connection fails then another broker is chosen, if available  
Zeroconf zeroconf:_activemq.broker.development. Uses Zeroconf to connect to an available broker of the correct Zeroconf service name. If multiple brokers can be found then one is chosen at random. If the connection fails then another broker is chosen, if available  
HTTP http://host:port Client connects to the broker using HTTP tunnelling, with XML payloads suitable for going through firewalls Yes
UDP udp://host:port Client connects to the broker at the given URL  
multicast multicast://host:port No server, though only works for pub/sub. A pure peer based network where all traffic is multicasted around and filtering is performed on the client.  
JGroups jgroups:config Reliable multicast using JGroups. No server, though only works for pub/sub. The value of config can be
jgroups:default
which uses the default JGroups settings, or a full JGroups configuration strings like
jgroups:UDP(mcast_addr=228.10.9.8;mcast_port=5678):PING:FD:GMS
In addition you can specify an XML configuration file to fully configure the JGroups config file via
jgroups:src/config/jgroups.xml
or using a full HTTP URL such as
jgroups:http://www.acme.com/jgroups/default.xml
 
jrms jrms://host:port Reliable multicast. No server, though only works for pub/sub  
JXTA jxta://host:port Client connects to server via JXTA protocol  

The Server? column above indiciates whether or not a protocol can be used in an ActiveMQ broker transport connector. All of the above protocols can be used in a JMS client to connect to the messaging fabric; only those protocols indicated can be used in a broker-side transport connector.

When connecting to an ActiveMQ broker, this could reside locally inside your JVM or be remote on another machine somewhere. If you want to enable the deployment of the ActiveMQ inside your JVM you can enable the useEmbeddedBroker property on the ActiveMQConnectionFactory.

Please refer to the topologies overview to see how we can use ActiveMQ in many different topologies to suit your messaging needs.

Specifying multiple URLs to connect to

You can specify a list of URLs to connect to (for example if you have message brokers running on a number of machines). To specify a list of URLs, use a comma separated list of URLs with a prefix of list:. e.g.

list:tcp://localhost:61699,tcp://localhost:61617,tcp://localhost:61698

If you want full HA to provide failover and auto-reconnection you can use the reliable: prefix instead

reliable:tcp://foo:61699,tcp://bar:61617,tcp://whatnot:61698

see Configuring Transports for more details

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