Question

One of the legal modifiers you can use with method local inner classes is abstract.

For example:

public class Outer {
    public void method(){
        abstract class Inner{
        }
    }
}

Is there any situation where you would actually use this?

You have to know this for the SCJP exam.

Answer 1

The are some invalid assumptions in the original question. That something is legal/valid Java doesn’t mean that it is something that you need to use, or need to know.

I can’t recall that the SCJP contains odd corner case questions.

I tried to come up with a case where I would have used an abstract class declared in a method, but everything looks very odd, and reeks of bad design.
Here’s however a code example that I came up with (still bad code design IMHO)

public class BatchExecutor {

    public static enum ResultNotification {
        JMS,
        MAIL
    };

    public Runnable createRunnable(ResultNotification type) {
        abstract class Prototype implements Runnable {
            public void run() {
                performBusinessLogic();
                publishResult();
            }

            abstract void publishResult();
        }

        switch (type) {
            case JMS: {
                return new Prototype() {
                    void publishResult() {
                        //Post result to JMS
                    }
                };
            }
            case MAIL: {
                return new Prototype() {
                    void publishResult() {
                        //Post result to MAIL
                    }
                };
            }
        }
        return null;
    }

    private void performBusinessLogic() {
        //Some business logic
    }

}