Method Overriding in Java | In Hindi

Summary

In this video, Anand explains the concept of method overriding in object-oriented programming, using a detailed example to illustrate how base and derived classes interact. He covers the importance of understanding overriding and the behavior of functions when they share the same name in different classes. Anand emphasizes how method overriding enables dynamic behavior, where the most specific class method is called. The tutorial also touches on how to prevent overriding by using 'final' methods and explains the technical nuances with simple code examples, making the concept accessible for viewers.

Takeaways

• 😀 Function overriding allows a subclass to provide its own implementation of a method that is already defined in the base class.
• 😀 The system first checks the subclass for the method when it is called; if not found, it looks in the base class.
• 😀 If a method is defined in both the base and derived class with the same name, the derived class method will be called due to overriding.
• 😀 Method overriding enables polymorphism, where different classes can provide their own specific behavior for the same method.
• 😀 The `final` keyword can be used to prevent a method from being overridden in subclasses, making the method 'final'.
• 😀 When overriding a method, the method signature (name, parameters) must remain the same in both the base and derived class.
• 😀 To prevent method overriding in a derived class, simply mark the base class method as `final`, ensuring it cannot be redefined.
• 😀 Function overriding is commonly used in object-oriented programming to ensure that subclass behavior can extend or change the base class's functionality.
• 😀 If a method in the base class is marked as `final`, attempting to override it in any subclass will result in a compilation error.
• 😀 The concept of method overriding helps in achieving flexibility in code, allowing objects of different classes to behave differently even when using the same method.
• 😀 Anand uses a code example to demonstrate the behavior of overriding by defining similar methods in the base and derived classes and calling them in various scenarios.

Q & A

What is function overriding in object-oriented programming?

Function overriding occurs when a subclass provides a specific implementation for a method that is already defined in its parent class. The subclass's method 'overrides' the parent class's method when called on an object of the subclass.

Why is function overriding important in object-oriented programming?

Function overriding is important because it allows subclasses to modify or extend the behavior of methods inherited from the base class, promoting code reuse and enabling polymorphism in object-oriented programming.

What happens if a function in the subclass has the same name and parameters as a function in the base class?

If a function in the subclass has the same name and parameters as a function in the base class, the subclass function will override the base class function. The version of the function in the subclass is called when the method is invoked on an object of the subclass.

How does an object determine which function to call when both the base class and subclass have the same function name?

When an object of the subclass calls the function, the object first looks for the method in the subclass. If found, it is called. If not, it checks the base class for the method. This behavior is due to inheritance, with the subclass taking precedence.

What is the role of the 'final' keyword in preventing function overriding?

'final' is used to prevent a method from being overridden in any subclass. When a method is marked as final, the subclass cannot provide its own version of the method, ensuring the method's behavior remains unchanged.

Can you override a final method in a subclass?

No, you cannot override a final method in a subclass. The final keyword locks the method in the base class, making it unmodifiable by subclasses.

In the script, how is function overriding demonstrated using the example of Class A and Class B?

In the script, Class A has a method called 'display'. Class B, which inherits from Class A, also defines a 'display' method. When an object of Class B is created and the 'display' method is called, the version in Class B is executed, overriding the version in Class A.

What does the speaker mean by 'overriding a function means ignoring the base class function'?

The speaker is emphasizing that when a subclass overrides a function, it essentially ignores the base class's version of the function. The method in the subclass is the one that gets executed instead.

What is the relationship between function overriding and polymorphism in object-oriented programming?

Function overriding is a key component of polymorphism, which allows the same method call to invoke different behaviors depending on the type of object (i.e., the subclass) on which it is called. This is an example of dynamic method dispatch in action.

How can you prevent a function from being overridden in a subclass in Java or similar languages?

You can prevent a function from being overridden by declaring it as 'final' in the base class. This ensures that subclasses cannot provide their own version of the function, thus preserving the behavior defined in the base class.