DoubleParenthesis.java

class Parent {
    private int a = 10;

    void addTwo() {
        a += 2;
    }

    void showValueOfA() {
        System.out.println(a);
    }
}

public class Main {
    public static void main(String[] args) {
        // anonymous class
        new Parent() {{
            // no need to mention the keyword "this"
            addTwo();
            addTwo();
            addTwo();
            showValueOfA();
        }};
    }
}

// Output: 16