Use this task to configure Enterprise JavaBeans (EJB) 3.1 session bean methods to run asynchronously. You can make some or all of your bean methods asynchronous.
You can create a bean implementation class for a stateful session bean as introduced in the Enterprise JavaBeans™ (EJB) 1.0 specification and significantly simplified by the EJB 3.0 specification. A stateful bean is a type of session bean that is intended for use by a single client during its lifetime and maintains a conversational state with the client that is calling it.
Create a bean implementation class for a singleton session bean, introduced by the Enterprise JavaBeans (EJB) 3.1 specification. The EJB container initializes only one instance of a singleton session bean, and that instance is shared by all clients. Because a single instance is shared by all clients, singleton session beans have special life cycle and concurrency semantics.