OnJava8-Examples/innerclasses/AnonymousConstructor.java

// innerclasses/AnonymousConstructor.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Creating a constructor for an anonymous inner class

abstract class Base {
  Base(int i) {
    System.out.println("Base constructor, i = " + i);
  }
  public abstract void f();
}

public class AnonymousConstructor {
  public static Base getBase(int i) {
    return new Base(i) {
      { System.out.println(
        "Inside instance initializer"); }
      @Override public void f() {
        System.out.println("In anonymous f()");
      }
    };
  }
  public static void main(String[] args) {
    Base base = getBase(47);
    base.f();
  }
}
/* Output:
Base constructor, i = 47
Inside instance initializer
In anonymous f()
*/