We create a base class Shape, Circle and Square then inherit Shape.
First case: Circle Square and not cover the base class.
class Shape {
public void draw() {
System.out.println("Shape!");
}
}
class Circle extends Shape {
}
class Square extends Shape {
}
public class Demo03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Circle c = new Circle();
c.draw();
Square s = new Square();
s.draw();
}
}
result:
Second case: Circle Square covering the base class method does not cover the method of the base class.
class Shape {
public void draw() {
System.out.println("Shape!");
}
}
class Circle extends Shape {
public void draw() {
System.out.println("Circle!");
}
}
class Square extends Shape {
}
public class Demo03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Circle c = new Circle();
c.draw();
Square s = new Square();
s.draw();
}
}
result:
The third case: Circle Square and base class methods are covered.
class Shape {
public void draw() {
System.out.println("Shape!");
}
}
class Circle extends Shape {
public void draw() {
System.out.println("Circle!");
}
}
class Square extends Shape {
public void draw() {
System.out.println("Square!");
}
}
public class Demo03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Circle c = new Circle();
c.draw();
Square s = new Square();
s.draw();
}
}
result:
Conclusion: If the derived class does not cover the base class, the base class is then automatically run; method of deriving class covering covers the lead out if the base class, then run.