Abstract
- Method overriding occurs when a child class provides its own implementation of a method that already exists in its parent class. The overriding method in the child class must have the same function signature (in Java, this includes the return type and function signature) as the method it is overriding in the parent class
Java method overriding
In Java, method overriding happens when a subclass defines an instance method with the same method descriptor as superclass. The return type can be different if it is a subtype of the return type of the method in the parent class.
As a good practice, use @Override to ensure method overriding is carried out.
Why is this useful?
Method overriding enables different objects to respond to the same method call in a way that’s specific to their type, thus fulfilling the OOP principle of polymorphism.
@Override
- A flag in Java that helps the compiler catch errors when overriding methods by telling the compiler a method is intended to override another method
Ensure proper method overriding
If a programmer intends to override a method from the parent class but misspells the method name or changes the signature, the compiler would normally treat it as a new method in the child class.
The
@Overrideannotation prevents this by explicitly signalling to the compiler that the method should override an existing method in the parent class. If the method doesn’t correctly override a parent class method, the compiler will generate an error.
Can I not change anything in the method overriding?
The method will still be considered a valid override. The
@Overrideannotation simply indicates that a method is intended to override a method from the superclass, and it doesn’t enforce any specific change in behaviour.
What if the current class puts
@overridefor a method that isn't inside the superclass?
@Overrideannotation specifically indicates that the method is meant to override a method from the superclass. If no such method exists, it signals an error.