Is it mandatory to implement all the methods of an interface in C#?

Yes, it is mandatory to implement all the methods in a class that implements an interface until and unless that class is declared as an abstract class. Implement every method defined by the interface.

Why do we need default method in Java 8 interfaces?

Java 8 allows the interfaces to have default and static methods. The reason we have default methods in interfaces is to allow the developers to add new methods to the interfaces without affecting the classes that implements these interfaces.

What is the use of methods in Java?

A method is a collection of statements that perform some specific task and return the result to the caller. A method can perform some specific task without returning anything. Methods allow us to reuse the code without retyping the code.

In which case we can implement only required methods of an interface?

8 Answers. If you don’t implement all the methods of the interface , your class must be abstract , in which case you can’t create an instance of it. In Java 8, if your interface contains default implementations for some methods, you don’t have to implement them in classes that implement the interface.

What happens if we dont implement all methods of interface?

If you don’t implement all methods of your interface, than you destroy the entire purpose of an interface. We can override all the interface methods in abstract parent class and in child class override those methods only which is required by that particular child class.

What is the purpose of default method in interface?

Default methods enable you to add new functionality to existing interfaces and ensure binary compatibility with code written for older versions of those interfaces. In particular, default methods enable you to add methods that accept lambda expressions as parameters to existing interfaces.

Why do we need default and static methods in interface?

Static Method: Default methods enable you to add new functionality to the interfaces of your libraries and ensure binary compatibility with code written for older versions of those interfaces. A static method is a method that is associated with the class in which it is defined rather than with any object.

What is difference between function and method in Java?

A method is a procedure or function in object-oriented programming. A function is a group of reusable code which can be called anywhere in your program. This eliminates the need for writing the same code again and again.

How methods are declared in Java?

Java requires that a method declare the data type of the value that it returns. If a method does not return a value, it must be declared to return void . However, the pop() method in the Stack class returns a reference data type: an object. Methods use the return operator to return a value.

What happens if we change the arguments of overriding method?

4) What happens if we change the arguments of overriding method? If we change the arguments of overriding method, then that method will be treated as overloaded not overridden.

Why should a method be overridden in Java instead of writing a method with a different name?

2) Method Overriding is useful to add extra functionality or code to a method of subclass with the same name as the inherited method.