CODEWITHSUNDEEP
javaannotationsjax-ws
neo
neo

Reputation: 2471

Jax-ws @PreDestroy When does it get called exactly?

I have a simply web service using @PostConstruct and @PreDestory annotations. 

@PostConstruct
private void init() {...} //initialize some database connection

@PreDestroy
private void release() {...} //release data base resources

then a client will call some web methods to do some database operations. I did a simply testing by setting break points in the code. The @PostConstruct works fine. but @PreDestroy method never get called.

I thought @PreDestroy will always get called when a client finish calling a web method since web service is stateless by nature. So in the end, the instance is always destroyed and before that, my release method should be called? Is this a correct understanding?

But after reading some online resources, i got confused. some says @PreDestroy will be called when it's un-deployed?

Upvotes: 2

Views: 3402

Answers (1)

mtpettyp
mtpettyp

Reputation: 5569

@PreDestroy is only called when the application server decides to reduce the size of the Method-Ready pool - i.e. it determines it doesn't need to keep as many instances of your @WebService @Stateless session bean around. It doesn't get called after each invocation of your @WebMethod (and @PostConstruct is only called when a new instance is added to the Method-ready pool, not necessarily before each web method invocation).

If you have logic you need called before and after each method invocation you could do it as follows:

@AroundInvoke
public Object intercept( InvocationContext ctx )
{
  try
  {
    init();
    return ctx.proceed();
  }
  finally
  {
    release();
  }
}

This method can be added to your @WebService bean or as a separate class using @Interceptors

Upvotes: 7

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