Q:

Java, EJB, Concurrency lock for all methods

I have EJB with two methods
@Singleton(name = "RatingCalculatorEJB")
public class RatingCalculatorBean {

    public void countRating() {}

    public void countRating(int someID) {}
}

By default all methods has concurrency lock: @Lock(LockType.WRITE)
If method invoked by any thread - another thread will wait to invoke this method.
But I need more - if any method invoked by a thread, all other threads that call any method of EJB should wait.
Does I have any way to do it?
The same question for @Stateless beans

A:

@Lock(LockType.WRITE) locks ALL EJB methods of the bean, so it already does what you want. 
Stateless beans only handle one client at a time, so concurrency should rarely be a problem there.

