Welcome, fellow Java Enthusiasts, In this blog we are going to understand the concept of method overriding and explore the strategies of how to prevent method overriding. While method overriding is a great feature in Java but there are a few situations where you might need to save the stability and integrity of the code.

If you want to know how to prevent method overriding in Java, reading this blog will help you to explore ways to prevent overriding. But before we dive into prevention techniques, let’s understand what method overriding entails.

What Is Method Overriding in Java?

When methods of the subclass having the same name as that of the superclass, overrides the methods of the superclass then it is called overriding methods. It is the concept of run-time polymorphism or late binding.

Also, it is known as the dynamic binding at the run-time. The concept when a method of one subclass overrides the same method in its superclass, but with a different implementation, is known as Method Overriding in Java.

Why Do We Use Method Overriding?

Overriding is used for runtime polymorphism and it is used to provide the specific implementation of the method which is already given by its superclass.

Overriding is used when we have two classes with similar codes. There are several reasons for which method overriding is used:

• Polymorphism: One of the fundamental ideas of object-oriented programming is polymorphism, which is made possible via method overriding. Due to polymorphism, various objects can respond to the same method call in various ways depending on how they were implemented. This adaptability and dynamic behavior encourage effective object interactions and code reuse.
• Customization and Specialisation: A subclass can modify and specialize the behavior it inherited from its superclass by overriding a method. This gives developers the ability to modify and increase the functionality of existing classes to meet certain needs. It enables method customization and fine-tuning to better suit the particular requirements of subclasses.
• Extend Capabilities & Functionality:  Method overriding enables subclasses to expand upon and improve upon the superclass’s capabilities. Subclasses might modify the behavior, provide new features, or add more logic to the inherited function. As a result, code reuse is encouraged and a hierarchical structure is fostered, with subclasses building on the superclass’s basis.
• Consistent Interface: The use of method overriding keeps a hierarchy of classes’ interfaces uniform. Subclasses offer a standardized manner of dealing with objects by adhering to the method signature specified in the superclass. This makes using objects easier and guarantees compatibility while working with various instances of related classes.
• Runtime Polymorphism: Method overriding makes it possible for runtime polymorphism, in which the best method implementation is determined based on the actual type of the object. This encourages loose connectivity between objects and flexibility in the method invocation. It improves the codebase’s adaptability and flexibility, making it simpler to extend and modify.
• Frameworks and Inheritance-based Design: Frameworks and inheritance-based design patterns both make use of method overriding to a significant extent. Frameworks frequently specify a collection of methods that subclasses can override to alter behavior. Method overriding is a key component of inheritance-based design patterns like the Template Method and Strategy patterns, which offer a variety of implementations for particular actions or tactics.

Advantages of using Method Overloading

Some key advantages of method overriding are as follows-

• Polymorphism: Overriding allows a subclass to provide its own implementation method, which we can use to create more specific objects, and they behave differently depending on their type.
• Code Reusability: By providing a new implementation of a method in the subclass, we can reuse the code from the superclass and avoid duplicating code. By making our code reusable we can save time and reduce the risk of errors.
• Flexibility: By allowing the subclasses to provide their own implementations of methods, we can create more specialized classes that are tailored to specific use cases.

Disadvantages of Method Overriding

• In Method Overriding, we cannot override a method if the classes are not in inheritance.
• In Method Overriding, we cannot override a method outside the package.
• In Method Overriding we cannot reduce the visibility of the overridden method.
• In Method Overriding we cannot override the private, static, and final keywords.

Rules of Method Overriding

Java’s method overriding adheres to a set of rules to ensure proper polymorphic and inherited behavior. The following are the main guidelines to remember when overriding methods:

• Inheritance Relationship: Inherited methods can only be overridden. Method Overriding can only take place between a superclass and its subclass. The subclass also needs to inherit the method from its superclass.
• Return Type: The return type stated in the overridden method and the return type of the overriding method must be compatible. The overriding method may return the same type or a subtype (covariant return type) if the overridden method returns a particular type.
• Method Signature: The superclass method being overridden must have the same method signature (method name, return type, and parameter list) as the overriding method. The order, types, and number of parameters in the method signature must all match.
• Access Modifier: The overriding method’s access modifier shouldn’t be more stringent than the overridden method’s. The overriding method may be protected or public, for instance, if the superclass declares the overridden method to be public. It cannot have default (package-private) access or be private. In simple words, the method must not have a more restrictive access modifier, or it must not throw new or broader checked exceptions.
• Exception Handling: In contrast to the exceptions thrown by the overridden method, the overriding method should not throw checked exceptions that are broader (higher up in the exception hierarchy). However, it is permitted to throw fewer, narrower, or even no exceptions at all. The checked exceptions that the superclass method declares may or may not be thrown by subclasses.
• Use of @Override Annotation: Using the @Override annotation before the declaration of the overriding method is recommended but not mandatory. When a method is not actually overriding a method from a superclass, this annotation aids in the detection of mistakes at compile time. Additionally, it clarifies the objective and makes the code easier to comprehend.

Method overriding combines inheritance and polymorphism, it makes an excellent tool for removing common code issues, such as excessive conditionals and utility classes that could become less prevalent through wise use of overriding. 

Keep in mind that instance methods, unlike static methods, are subject to method overriding. Java resolves static methods at compile time using the reference type rather than at run time using the actual object type. As a result, static methods can only be shadowed in subclasses and not overridden.

Ways To Prevent Method Overriding

Below, we have mentioned the five ways to prevent method overriding in Java:

1. By declaring the method as final or using the final keyword:  The final keyword in the superclass indicates that a method cannot be overridden by any subclass before a method declaration. As a result, the method’s implementation is guaranteed to be consistent across the class hierarchy.

2. By using a private access modifier in the overriding method: A method’s visibility is restricted to the class in which it is defined when it is declared private. Subclasses cannot access private methods, hence they cannot be overridden.

3. By using the final class: You can declare the class itself as ‘final’ if you want to prevent the entire class from being subclassed and its methods from being overridden. Doing this will ensure that any of the subclasses can be created, further preventing method overriding.

4. By using the static keyword: We can also prevent Method overriding by using the static method instead of the non-static method.Java classes themselves are responsible for static methods rather than specific instances. On the basis of the reference type, they are resolved at compile time. Static methods cannot be overridden since they are not connected to object inheritance.

5. By declaring the class as final: You can prevent subclasses from extending and inheriting from a class by declaring it as final. This effectively prevents all methods in the class from being overridden.

Conclusion

You may reliably maintain the integrity of your code, maintain predictability, and ensure the stability of your applications by mastering the ways to prevent method overriding in Java as we mentioned above.

Always keep in mind that method overriding is a strong technique that encourages flexibility and code reuse. To establish a balance between control and extensibility, use these preventative strategies sparingly and only when necessary. You can build reliable, maintainable, and predictable Java applications by knowing when and how to avoid method overriding.