The J2EE Engine provides failover services for RMI-P4 applications that run on it. These services refer to the mechanism of migrating remote objects from the crashed server process to an available server process in the cluster.
For a detailed description of this mechanism, see Failover for Clustered RMI-P4 Remote Objects in the Development Manual.
The failover of entity and stateless session beans is performed following the mechanism mentioned above. The EJB Container takes care of generating the appropriate code so that those types of beans are redirectable.
The failover for stateful session beans provides also options for state preservation after the object is being migrated to a new server process. You must explicitly enable the stateful session failover using the EJB application’s descriptors.
For more detailed information about the different types of failover for enterprise beans, see Failover for Enterprise Beans in the Development Manual.