Thread spawning libraries in EJB

Question

Is it allowed to use libraries inside an EJB which are spawning and manage threads?

I wrote a JavaSE library with a class like this:

public class LibraryClass {
    public void longRunningMethod() {
        ExecutorService service = Executors.newFixedThreadPool(10);
        //schedule tasks
        service.shutdown();
        try {
            service.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

Example EJB:

@Stateless
class Bean {
    public void beanMethod() {
        LibraryClass libraryClass = new LibraryClass();
        libraryClass.longRunningMethod();
    }
}

Would it be ok to use something like this inside an EJB?

The specification states that "The enterprise bean must not attempt to manage threads", would this still apply if the threads are managed outside of the EJB, maybe even out of control of the developer (for example when using 3rd party libraries)?

Answer 1

Hi in general the suggestion is true. It is a bad practice, since you are already running on a 'contained' environment that already does the heavy lifting of thread handling /hread pooling (allocation) for you. In case that you really want to span threads you should, make sure that the container is aware of them or provide him the constructs so that it can handle and monitor it. This is materialized with the use of the Executor Service in Java.See here and here