OnJava8-Examples/typeinfo/Shapes.java

// typeinfo/Shapes.java
// (c)2017 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.
import java.util.stream.*;

abstract class Shape {
  void draw() { System.out.println(this + ".draw()"); }
  @Override
  public abstract String toString();
}

class Circle extends Shape {
  @Override
  public String toString() { return "Circle"; }
}

class Square extends Shape {
  @Override
  public String toString() { return "Square"; }
}

class Triangle extends Shape {
  @Override
  public String toString() { return "Triangle"; }
}

public class Shapes {
  public static void main(String[] args) {
    Stream.of(new Circle(), new Square(), new Triangle())
      .forEach(Shape::draw);
  }
}
/* Output:
Circle.draw()
Square.draw()
Triangle.draw()
*/