What is the difference between stateful session bean and entity bean

Entity Beans

- represents an entity

- must have at least one finderXXX() method

- may or may not have create() or createXXX() methods

- when you call remove() on an entity bean the entity is removed permanently but the bean instance goes back to the pool it never die's.

- Entity beans home interface can have Home Business methods

- Entity beans home methods may or may not return component interface object.

- Entity bean create() method creates a new row into the database whereas create() method in session bean doesn't.

- Entity bean's finder method that returns a collection will never throw a exception if it does not find related records in the underlying persistent storage instead it will return an empty collection.

- Entity beans will survive container crash as long as the data is persisted in the underlying storage.

Session Bean

- generally they are used to perform some actions(verbs)

- there are two types of SB stateless and stateful.

- should have at least one create() "no args" constructor (Stateless bean only)

- Stateless beans are more scalable then stateful beans.

- Stateless beans do not retain conversational state between method invocations.

- Stateless beans are not tied to a particular client whereas stateful beans are.

- The result of a client calling create() on home interface of a stateless SB does not result into creation of a bean but in stateful it does.

- There is no effect of calling remove() on Stateless session bean because the beans go back to the pool after the method call completes.

- session beans will never survive a container crash.

There are many more things we can talk about both bean types.

javaProa at 2007-7-9 6:06:33 >