What are Interceptors in Java EE?

Question

I\'m trying to clear my concept about Interceptors in Java EE. I have read Java EE specification but I\'m little confused about it. Please provide me some useful link or tutoria

Answer 1

Interceptors are used to implement cross-cutting concerns, such as logging, auditing, and security, from the business logic.

In Java EE 5, Interceptors were allowed only on EJBs. In Java EE 6, Interceptors became a new specification of its own, abstracted at a higher level so that it can be more generically applied to a broader set of specifications in the platform.

They intercept invocations and life-cycle events on an associated target class. Basically, an interceptor is a class whose methods are invoked when business methods on a target class are invoked, life-cycle events such as methods that create/destroy the bean occur, or an EJB timeout method occurs. The CDI specification defines a type-safe mechanism for associating interceptors to beans using interceptor bindings.

Look for a working code sample at:

https://github.com/arun-gupta/javaee7-samples/tree/master/cdi/interceptors

Java EE 7 also introduced a new @Transactional annotation in Java Transaction API. This allows you to have container-managed transactions outside an EJB. This annotation is defined as an interceptor binding and implemented by the Java EE runtime. A working sample of @Transactional is at:

https://github.com/arun-gupta/javaee7-samples/tree/master/jta/transaction-scope