OnJava8-Examples/polymorphism/PolyConstructors.java at master · CSapprenticeWT/OnJava8-Examples · GitHub

Repository navigation

// polymorphism/PolyConstructors.java

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// Constructors and polymorphism

// don't produce what you might expect

class Glyph {

void draw() { System.out.println("Glyph.draw()"); }

Glyph() {

System.out.println("Glyph() before draw()");

draw();

System.out.println("Glyph() after draw()");

}

class RoundGlyph extends Glyph {

private int radius = 1;

RoundGlyph(int r) {

radius = r;

System.out.println(

"RoundGlyph.RoundGlyph(), radius = " + radius);

}

@Override void draw() {

System.out.println(

"RoundGlyph.draw(), radius = " + radius);

}

public class PolyConstructors {

public static void main(String[] args) {

new RoundGlyph(5);

}

/* Output:

Glyph() before draw()

RoundGlyph.draw(), radius = 0

Glyph() after draw()

RoundGlyph.RoundGlyph(), radius = 5