Language and Page Formatting Options
6.6. Clustered Enterprise JavaBeans
6.6.1. About Clustered Enterprise JavaBeans (EJBs)
EJB components can be clustered for high-availability scenarios. They use different protocols than HTTP components, so they are clustered in different ways. EJB 2 and 3 stateful and stateless beans can be clustered.
For information on singletons, refer here: Section 7.4, “Implement an HA Singleton”.
EJB 2 entity beans cannot be clustered. This limitation is not expected to be changed.