In order to deploy EJB3s, all .jar files must be examined for the existence of annotated classes and EJB3 style deployment descriptors. This can significantly slow the deployment if there are large numbers of .jar files, xml descriptors, and classes that need to be examined. In order to provide a mechanism to speed the deployment time in these scenarios, JBoss EJB3 provides a flag which will cause the EJB3 deployer to only examine .ejb3 files for the existence of annotated classes and EJB3 style deployment descriptors.
Take a look at jboss-service.xml. This file is found in the deploy/ejb3.deployer directory. The jboss.ejb3:service=EJB3Deployer mbean configuration contains a DeployEjb3ExtensionOnly attribute. The default value for this atrribute is false, which indicates that all .jar files should be examined for annotated classes and EJB3 style deployment descriptors. Setting the value to true will cause the EJB3 deployer to only examine files with .ejb3 extensions.