Here is an example of how inheritance works in JAVA:
public class Rectangle
{
// define instance variables:
protected double width, height;
// define setter methods:
public Rectangle (double w, double h ) {
width = w;
height = h;
}
// define other methods:
public double calcArea() {
return width * height;
}
public double calcPerimeter() {
return 2 * (width + height);
}
}
public class Square extends Rectangle
{
public Square(double side {
super(side, side);
}
}
Class Square is derived from a base class Rectangle. Thus, public variables and methods of Rectangle are inherited in Square class. Notice the use of keyword �extends� to derive a child class (Square) from a parent class (Rectangle).