An anonymous inner class that calls the base-class constructor : Anonymous inner class « Class Definition « Java Tutorial

1. Java Tutorial
2. Class Definition
3. Anonymous inner class

public class MainClass {
  public A wrap(int x) {
    // Base constructor call:
    return new A(x) { // Pass constructor argument.
      public int value() {
        return super.value() * 47;
      }
    }; // Semicolon required
  }

  public static void main(String[] args) {
    MainClass p = new MainClass();
    A w = p.wrap(10);
  }
}

class A {
  private int i;

  public A(int x) {
    i = x;
  }

  public int value() {
    return i;
  }
}