Method overriding in Java

Overriding is the ability to define a behavior that's specific to the subclass type, which means a subclass can implement a parent class method based on its requirement.

In object-oriented terms, overriding means to override the functionality of an existing method.

Example

Let us look at an example.

class Animal {
   public void move() {
      System.out.println("Animals can move");
   }
}
class Dog extends Animal {
   public void move() {
      System.out.println("Dogs can walk and run");
   }
}
public class TestDog {
   public static void main(String args[]) {
      Animal a = new Animal(); // Animal reference and object
      Animal b = new Dog();  // Animal reference but Dog object
      a.move();  // runs the method in Animal class
      b.move(); // runs the method in Dog class
   }
}

Output

This will produce the following result −

Animals can move
Dogs can walk and run

In the above example, you can see that even though b is a type of Animal it runs the move method in the Dog class. The reason for this is: At compile time, the check is made on the reference type. However, in the runtime, JVM figures out the object type and would run the method that belongs to that particular object.
Therefore, in the above example, the program will compile properly since Animal class has the method move. Then, at the runtime, it runs the method specific for that object.