Method Overriding in Java

• Overriding is a feature that allows a subclass or child class to provide a specific implementation of a method that is already provided by one of its super-classes or parent classes.
• When a method in a subclass has the same name, same parameters, and same return type(or sub-type) as a method in its super-class, then the method in the subclass is said to override the method in the super-class.
• Method overriding is one of the way by which java achieve Run Time Polymorphism.

Usage of Java Method Overriding

• Method overriding is used for achieving run-time polymorphism.
• Method overriding is used for writing specific definition of a subclass method (this method is known as the overridden method).

Rules for Overriding

• Method name must be the same
• Parameters must be the same
• Return type must be the same (or compatible)
• It must be in a parent-child (inheritance) relationship
• Java picks which method to run at run time, based on the actual object type, not just the reference variable type.

Example

class Vehicle{  
    void run(){
        System.out.println("Vehicle is running");
    }  
}  

class Bike extends Vehicle{  
    void run(){
        System.out.println("Bike is running safely");
    }  

    public static void main(String args[]){  
        Bike obj = new Bike();  
        obj.run(); 
    }  
}  

Output
Bike is running safely