In object oriented Java, what is the use and benefit of method overriding?

Introduction / Context:
Method overriding is a fundamental feature of object oriented programming in Java. It allows subclasses to customize or extend the behavior defined in a superclass while keeping the same method signature. This capability is central to runtime polymorphism, where different object types can respond differently to the same method call. This question asks you to explain the purpose and benefits of overriding in Java applications.

Given Data / Assumptions:
- There is at least one superclass with methods that subclasses may want to specialize.
- Subclasses can override methods by using the same signature and compatible return type.
- The code may handle objects through superclass references but deal with many concrete subclasses at runtime.
- We are focusing on behavior customization, not on compilation speed or static transformations.

Concept / Approach:
Method overriding occurs when a subclass declares a method with the same name, parameter list and compatible return type as a method in its superclass. When this happens, the subclass method replaces the superclass method for instances of the subclass. At runtime, the Java Virtual Machine chooses the implementation to execute based on the actual object type, not on the reference type, which is dynamic dispatch. This allows us to write generic code that calls a method on a superclass reference while getting behavior that is appropriate for each subclass.

Step-by-Step Solution:
Step 1: Recall that overriding requires the same method signature in both superclass and subclass. Step 2: Understand that when a method is overridden, calling it on a subclass instance executes the subclass version, even if the reference type is the superclass. Step 3: Recognize that this enables polymorphic designs where different subclasses implement the same abstract behavior in different ways. Step 4: Note that overriding does not automatically change return types arbitrarily, except for covariant return types that are compatible. Step 5: Choose the option that emphasizes customized behavior and runtime polymorphism as the main benefits.

Verification / Alternative check:
As an example, consider a superclass Shape with a method draw(), and subclasses Circle and Rectangle that override draw(). A list of Shape references can hold both Circle and Rectangle objects. When you iterate through the list and call draw() on each reference, the Java runtime will execute the correct version based on whether the object is a Circle or a Rectangle. This is the essence of polymorphism and is made possible by overriding. None of the other options about changing return types or compilation speed match this behavior.

Why Other Options Are Wrong:
Option B claims that overriding is mainly for changing the return type from void to int, which is not the purpose of overriding and is not generally allowed unless the types are covariant.
Option C states that overriding converts all methods into static methods, which conflicts with the actual definition of overriding and dynamic dispatch.
Option D suggests that overriding only affects compilation speed and not runtime behavior, which ignores the central role of overriding in polymorphism and method dispatch.

Common Pitfalls:
A common mistake is accidentally overloading instead of overriding a method by changing its parameters, which leads to unexpected behavior because the superclass method is still called in some contexts. Another pitfall is forgetting to use the @Override annotation, making it harder to spot errors in method signatures. Some developers also misuse overriding to add unrelated behavior instead of designing clear class hierarchies. Understanding overriding helps create maintainable code where subclasses behave as expected when used through superclass interfaces.

Final Answer:
The correct explanation is overriding allows a subclass to provide its own implementation of a method defined in a superclass, enabling runtime polymorphism and specialized behavior.