Question

What is the difference between overriding and overloading a method?

Short answer

Overloading enables same method names with different parameters; overriding allows subclasses to provide specific implementations of parent methods.

Step-by-step solution

Define Method Overloading

Method overloading occurs when two or more methods in the same class have the same name but different parameters (either in number, type, or both). It allows a class to perform a single action in different ways, by using different sets of input parameters.

Define Method Overriding

Method overriding occurs when a subclass provides a specific implementation of a method that is already defined in its superclass. Overriding is used to achieve runtime polymorphism, allowing the subclass to offer behavior specific to its type.

Differentiate Based on Their Purpose

Method overloading is used to increase the readability of the program and to perform various types of operations with the same method name, supporting compile-time polymorphism. Method overriding allows for dynamic method dispatch or runtime polymorphism, enabling object-specific behavior modifications in subclasses.

Consider Their Impact on Polymorphism

Overloading is an example of compile-time (or static) polymorphism since the method call is resolved at compile time through parameter differentiation. Overriding is an example of runtime polymorphism because the call to an overridden method is resolved at runtime depending on the object type.

Usage Contexts

Use method overloading when the methods do fundamentally the same thing but require different input parameters to handle the operation. Use method overriding to provide a subclass-specific implementation of a method that is already defined in the parent class.

Key concepts

Runtime Polymorphism

Runtime polymorphism, also known as dynamic polymorphism, is a concept where the method to be executed is determined at runtime. This is opposed to at compile time, allowing for more flexibility in object-oriented programming. The core idea here is that the exact method that gets called isn't determined until the program is actually running. This provides the opportunity for a subclass to specifically implement or alter a method's behavior that was initially defined in its superclass.

To achieve runtime polymorphism, method overriding is primarily used. In this approach, a method in a subclass has the same name, return type, and parameters as a method in its superclass. When a subclass object calls this method, the overridden version in the subclass is executed, hence facilitating runtime decision-making. This allows the program to use subclass-specific features while maintaining the ability to refer to subclass objects using superclass references.

• Method overriding is pivotal in implementing runtime polymorphism, allowing method call resolution at program execution.
• It gives the program flexibility to call the desired method applicable at the context of a specific object.

Compile-Time Polymorphism

Compile-time polymorphism, also referred to as static polymorphism, is about method calls being resolved at the compile time rather than at runtime. This occurs through a process called method overloading, where several methods share the same name but differ in parameter type, number, or both. It's useful in cases where the same operation or action needs to be performed in a slightly different way depending on the input type or structure.

In method overloading, the correct method to be executed is determined when the program is being compiled. This is why it's called static polymorphism — binding of method calls happens at the compile-time itself. It boosts the program's readability and efficiency by enabling the use of the same method name with different functionalities depending upon different inputs.

• Method overloading implements compile-time polymorphism by resolving method calls using parameter differentiation.
• It enhances code readability and allows for variations in parameters, parameter order, or parameter types.

Subclass Implementation

Subclass implementation refers to the way a subclass, in an object-oriented programming structure, inherits features from its parent class and can also introduce its own distinct properties and behaviors. In this hierarchy, the subclass leverages the use of inherited properties and methods while also providing specific methods that alter or enhance functionalities inherited from the superclass.

The ability to override methods is a defining feature of subclass implementation. Using method overriding, a subclass can customize or refine methods inherited from its superclass, providing its own logic or behavior while still maintaining compatibility with the superclass method signature. This ability ensures that a subclass can fine-tune aspects of its inherited methods, thus achieving specific tasks while still being recognized as part of the general family of its superclass.

• Subclass implementation complements polymorphism by allowing subclasses to modify inherited methods' behavior.
• Through overriding, subclasses can have tailored behavior essential for runtime polymorphism.
• This facilitates code reuse and logical grouping of related classes in a class hierarchy.