What is overriding?

What is overriding?

We have discussed about overloading in the the previous post. Now we will discuss about overriding and its differences with overloading.

Overriding allows us to modify a method behavior at run time.

Here are the rules to make 2 overridden methods:
1. Methods must not take its arguments different. Here if a method is taking object of Class A then another method which is taking object of [Class B extends A] then it is allowed.
2. Overriding is done with its super class methods only.
3. Overriding does not allow overriding method to throw a new checked exception or a super class of the exception class that overridden method is throwing.

Example:
class A{
protected void display() throw SQLException{

}
}

class B extends A{

void display() Exception {

}

void display() IOException {

}

public void display(){

}

}

4. Overloading must not change its return return types. Here if a method is returning object of Class A then another method returning object of [Class B extends A] then it is allowed.
5. Overriding can change the access modifiers but overriding method should have less limiting access permission.
Example:

class A{

protected void display(){

}

}


class B extends A{

default void display(){

}

public void display(){

}

}

*** Red means not allowed and Green means allowed here.