Implementing multiple generic interfaces

Question

I need to handle events of two different types but I\'m running into the following issue:

The interface EventListener cannot be implemented more than once with diffe

Answer 1

There is only one handle(Object) method in reality. You are effectively write the same as

public class CompositeListener implements EventListener {
    public void handle(Object event) {
        if (event instanceof PriceUpdate) {
            ///
        } else if (event instanceof OrderEvent) {
            ///
        }
    }
}

Without this checking logic, you can't effectively call your event listener in any case.