Method Overriding in Java

• Using method overriding, a subclass can change the behavior of inherited methods to meet its specific needs. It allows a programmer to implement methods in a derived class that has the same signature as in the base class. Same signature means the same name, the same number of parameters, and their types appearing in the same order.
• You are not allowed to override a method that has the final modifier.
• The method of a base class is known as overridden method, and the derived class method is known as overriding method.
• The return type of overriding and overridden method must be same.
• You are not allowed to make an overridden method less accessible. For example- if you are overriding a public method then you cannot declare it private, default, and protected.

Example of Method Overriding

public class Animal
{
	public void sound()
	{
		System.out.println("Animal makes sound");
	}
}
class Dog extends Animal
{
	public void sound()
	{
		System.out.println("Dog barks");
	}
	public static void main(String args[])
	{
		Dog d = new Dog();
		d.sound();
	}
}

Output

Dog barks

Overriding of static method

A static method of a base class cannot be overridden, but a derived class can define a method with the same signature. This will hide base class static method, and you can't even call it with super keyword.

static methods inherited from a base class cannot be made non-static.

Example of static method overriding

Call base class static method with super keyword will give compile time error.

class Parent
{		
	public static void show()
	{
		System.out.print("Parent");
	}
}
class Child extends Parent
{	
	public static void show()
	{
		super.show();
		System.out.print("Child");
	}
	public static void main(String args[])
	{
		Child c = new Child();
		c.show();	
	}
}

Output

Compile time error

Making base class static method non-static in a derived class will also give compile time error.

class Parent
{		
	public static void show()
	{
		System.out.print("Parent");
	}
}
class Child extends Parent
{	
	public void show()
	{		
		System.out.print("Child");
	}
	public static void main(String args[])
	{
		Child c = new Child();
		c.show();	
	}
}

Output

Compile time error

Difference between Method Overriding and Overloading