Session bean encapsulates business logic only, it can be invoked by local, remote and webservice client.
It can be used for calculations, database access etc.
The life cycle of session bean is maintained by the application server (EJB Container).
Types of Session Bean
There are 3 types of session bean.
1) Stateless Session Bean: It doesn't maintain state of a client between multiple method calls.
2) Stateful Session Bean: It maintains state of a client across multiple requests.
3) Singleton Session Bean: One instance per application, it is shared between clients and supports concurrent access.