The PreDestroy annotation is used on methods as a callback notification to 
 signal that the instance is in the process of being removed by the 
 container. The method annotated with PreDestroy is typically used to 
 release resources that it has been holding. This annotation MUST be 
 supported by all container managed objects that support PostConstruct 
 except the application client container in Java EE 5. The method on which 
 the PreDestroy annotation is applied MUST fulfill all of the following 
 criteria:
 
 
 - The method MUST NOT have any parameters except in the case of
 interceptors in which case it takes an InvocationContext object as
 defined by the Interceptors specification.
- The method defined on an interceptor class MUST HAVE one of the
 following signatures:
 
 void <METHOD>(InvocationContext)
  
 Object <METHOD>(InvocationContext) throws Exception
  
 Note: A PreDestroy interceptor method must not throw application
 exceptions, but it may be declared to throw checked exceptions including
 the java.lang.Exception if the same interceptor method interposes on
 business or timeout methods in addition to lifecycle events. If a
 PreDestroy interceptor method returns a value, it is ignored by
 the container.
  
- The method defined on a non-interceptor class MUST HAVE the
 following signature:
 
 void <METHOD>()
  
- The method on which PreDestroy is applied MAY be public, protected, 
 package private or private.
- The method MUST NOT be static.
- The method MAY be final.
- If the method throws an unchecked exception it is ignored except in the 
 case of EJBs where the EJB can handle exceptions.