Method overloading and method overriding are two concepts in Java related to the behavior of methods in classes. Here are the key differences between method overloading and method overriding:
Definition:
Method Overloading: Method overloading refers to defining multiple methods in the same class with the same name but different parameter lists. The methods must have a different number or type of parameters.
Method Overriding: Method overriding occurs when a subclass provides a specific implementation for a method that is already defined in its superclass. The method signatures in the superclass and subclass must be the same.
Inheritance:
Method Overloading: Overloading is not related to inheritance. Overloaded methods can exist within the same class or even within unrelated classes.
Method Overriding: Overriding is specifically related to inheritance. The overridden method must exist in the superclass, and the subclass provides a new implementation.
Keyword Usage:
Method Overloading: No specific keyword is used for method overloading. Overloaded methods have the same name, and the compiler differentiates them based on the method signature.
Method Overriding: The @Override annotation is used in Java to indicate that a method is intended to override a method in the superclass. While the annotation is optional, using it helps catch errors at compile-time.
Access Modifiers:
Method Overloading: Overloaded methods can have different access modifiers (public, private, protected, or default) in the same class.
Method Overriding: Overriding methods must not reduce the visibility of the overridden method. If a method is public in the superclass, it must be at least public in the subclass.
Runtime Polymorphism:
Method Overloading: Overloaded methods are resolved at compile-time based on the method signature. This is known as compile-time or static polymorphism.
Method Overriding: Overriding is resolved at runtime based on the actual type of the object. This is known as runtime or dynamic polymorphism, and it is achieved through the use of the overridden method in the subclass.
In summary, method overloading involves defining multiple methods with the same name in a class, differentiated by their parameter lists. Method overriding, on the other hand, occurs in a subclass when it provides a specific implementation for a method that is already defined in its superclass. Overloading is resolved at compile-time, while overriding is resolved at runtime, providing a mechanism for achieving polymorphism in Java.