What is method overriding in java ?

If we have methods with same signature (same name, same signature, same return type) in super class and subclass then we say subclass method is overridden by super-class.
When to use overriding in java.

If we want same method with different behavior in super-class and subclass then we go for overriding.

When we call overridden method with subclass reference subclass method is called hiding the super-class method.

Example:-

//Java Program to illustrate the use of Java Method Overriding  
//Creating a parent class.  
class Vehicle {
    //defining a method  
    void run() {
        System.out.println("Vehicle is running");
    }
}
//Creating a child class  
class Car extends Vehicle {
    //defining the same method as in the parent class  
    void run() {
        System.out.println("Car is running safely");
    }

    public static void main(String args[]) {
        Bike2 obj = new Car(); //creating object  
        obj.run(); //calling method  
    }
}

Output:-

Car is running safely