Provide Support for Clustered Singleton MDBs.

Provide annotation and configuration support to mark such MDB deployments Clustered Singleton MDBs.

When "Clustered Singleton MDBs" are deployed in a cluster; only one node (server) is active to consume messages serially. When the node fails; another the active node's "Clustered Singleton MDBs" starts consuming the messages.

To mark an MDB as clustered singleton, one can either use the clustered-singleton xml element, like this:
<jboss:ejb-jar xmlns:jboss="http://www.jboss.com/xml/ns/javaee"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:c="urn:clustering:1.1"
xmlns:d="urn:delivery-active:1.1"
xsi:schemaLocation="http://www.jboss.com/xml/ns/javaee http://www.jboss.org/j2ee/schema/jboss-ejb3-2_0.xsd http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/ejb-jar_3_1.xsd"
version="3.1"
impl-version="2.0">
<c:clustering>
<ejb-name>HelloWorldQueueMDB</ejb-name>
<c:clustered-singleton>true</c:clustered-singleton>
</c:clustering>
</jboss:ejb-jar>

Or one can use the @org.jboss.ejb3.annotation.ClusteredSingleton in your MDB class.

This feature requires no extra configuration at the server, apart from running the service in a cluster.