Multithreading in a stateless session bean?

Question

The EJB 3.0 specification does not allow a business method of a stateless session bean to create new threads. Why is that? What is wrong with creating additional worker thre

Answer 1

One type of workaround:

import java.util.concurrent.Executor;
import javax.ejb.Asynchronous;
import javax.ejb.Stateless;

@Stateless
public class TransactionalExecutor implements Executor {

    @Override @Asynchronous
    public void execute(Runnable command) {
        command.run();
    }
}

Now you can use TransactionalExecutor as an executor:

@Stateless
public class SlowService {

    @Inject
    Executor command;

    public void invoke(){
        Runnable command = new Runnable() {
            @Override
            public void run() {
                // heavy task
            }
        };
        command.execute(command);
    }    
}