Lesson 8	Identity of the bean and using session bean handles
Objective	Describe how a bean is identified, acquire a bean's handle, then re-connect to that bean later using the handle.

Bean Identity and Session Bean Handles

In this section we look at bean identities and bean handles^[1].

Session bean identity

Session bean instances have no external identity.
The one-to-one relationship between the client and the instance means that no other party needs to know about the identity of the bean instance.
Within a client, you can compare two remote references to the same or different bean instances using the following method of the EJBObject:

if (beanA.isIdentical(beanB)) { 
.  .  .

Do not simply compare remote references using ==.
It is not guaranteed to give correct results. For example (beanA == beanB) may not work correctly.
Use isIdentical().

Using the handle

A handle relates to a specific EJBObject object. Thus, the handle can be used to "find" an already created bean instance.
The handle is retrieved from the EJBObject as follows:

javax.ejb.Handle handle = bean.getHandle();
// serialize the handle and store
 . . .

Once the client has the handle to the EJBObject of a bean instance, it can be serialized and written to stable storage.
Later, possibly in a different JVM, the handle can be de-serialized from stable storage and used to obtain a reference to the EJBObject as follows:

// load and de-serialize the handle
 .  .  .
// get the Remote object reference
bean = handle.getEJBObject();
String response = bean.sayHello();
 . . .

The handle will be valid as long as the bean instance has not been removed, or the container has not crashed and discarded the instance. Some containers will impose a timeout on an instance if it has not been accessed for a specific length of time, at which point the instance will be discarded.

Business Methods - Quiz

Click the Quiz link below to test your understanding of session bean business methods and exceptions and session bean handles.
Business Methods - Quiz
In the next lesson, you will review what you've learned in this module.

[1]Bean handle: A universal reference to a bean instance, that is available from the EJBObject, that can be used to re-connect to a bean at a later time.