Java Language Specification - Cannot understand 'BlockStatement'

Question

I\'ve been examining the Java Language Specification here (instead I should be out having a beer) and I am curious about what a method can contain. The specification states a me

Answer 1

As others have said, you can declare a class inside a method. One use case of this is to use this as an alternative for an anonymous inner class. Anonymous inner classes have some disadvantages; for example, you can't declare a constructor in an anonymous inner class. With a class declared locally in a method, you can.

Here's a silly example that doesn't really show why you'd want to do this, but at least how you could do it.

public Runnable createTask(int a, int b) {
    // Method-local class with a constructor
    class Task implements Runnable {
        private int x, y;

        Task(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public void run() {
            System.out.println(x + y);
        }
    }

    return new Task(a, b);
}