As an expert in object-oriented programming (OOP), I can provide you with an in-depth explanation regarding the use of the `final` keyword in conjunction with abstract classes and methods in Java, which is the context in which this question typically arises.

In the realm of OOP, an abstract class is a blueprint for other classes. It allows you to declare methods without implementing them, which means that you can specify what the method does but not how it does it. This is useful when you want to create a common interface for classes that will share similar properties and behaviors but you do not want to implement every method for each class.

On the other hand, the `final` keyword in Java serves a different purpose. It is used to prevent further inheritance or overriding. When a class is declared `final`, it cannot be subclassed. When a method is declared `final`, it cannot be overridden by subclasses. This is often used to ensure that a certain behavior is not changed or to indicate that a class or method is complete and should not be modified.

Now, let's address the question of whether you can make an abstract class `final`. The simple answer is no. The `final` keyword is inherently contradictory when applied to an abstract class because the purpose of an abstract class is to be extended. If you declare an abstract class as `final`, you would be negating its fundamental purpose, which is to serve as a base for other classes to inherit from and to implement the abstract methods.

Additionally, you cannot have a method that is both `abstract` and `final`. The reason is that an abstract method is one that is declared without an implementation and is intended to be overridden by a subclass. A `final` method, by contrast, cannot be overridden. These two concepts are mutually exclusive. Similarly, an abstract method cannot be `private` because `private` methods are not visible to subclasses and thus cannot be overridden, which defies the purpose of an abstract method.

To summarize, here are the key points:


1. Abstract Classes: Designed to be extended, cannot be instantiated on their own.

2. Final Classes: Cannot be subclassed, ensuring no other class can extend them.

3. Final Methods: Cannot be overridden by subclasses, ensuring the behavior is fixed.

4. Abstract and Final Methods: You cannot combine these keywords because they have opposing purposes.

In Java, the language enforces these rules, and any attempt to declare an abstract class as `final` or an abstract method as `final` or `private` would result in a compile-time error.

Now, let's proceed with the next steps as per your instructions.

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This is the same reason why abstract methods cannot have access modifier private. you cannot inherit final class , but abstract class can be inherit into subclasses. A method can never, ever, ever be marked as both abstract and final, or both abstract and private.Oct 1, 2013read more >>