Can we instantiate abstract class and interface?

Abstract class, we have heard that abstract class are classes which can have abstract methods and it can’t be instantiated. We cannot instantiate an abstract class in Java because it is abstract, it is not complete, hence it cannot be used.

Is interface and abstract class same?

The short answer: An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.

What is the main difference between interface and abstract class in Java?

Difference between abstract class and interface

Abstract class	Interface
2) Abstract class doesn’t support multiple inheritance.	Interface supports multiple inheritance.
3) Abstract class can have final, non-final, static and non-static variables.	Interface has only static and final variables.

Can we use abstract and interface together?

It’s perfectly normal to use these two together.

Can we declare final inside abstract class and interface both?

If you declare a class abstract, to use it, you must extend it and if you declare a class final you cannot extend it, since both contradict with each other you cannot declare a class both abstract and final if you do so a compile time error will be generated.

Can abstract classes be extended?

Abstract classes are similar to interfaces. You cannot instantiate them, and they may contain a mix of methods declared with or without an implementation. In addition, you can extend only one class, whether or not it is abstract, whereas you can implement any number of interfaces.

What is the difference between class and interface in Java?

A class describes the attributes and behaviors of an object. An interface contains behaviors that a class implements. A class may contain abstract methods, concrete methods. An interface contains only abstract methods.

What is abstract method and abstract class in java?

Abstract Classes and Methods Abstract class: is a restricted class that cannot be used to create objects (to access it, it must be inherited from another class). Abstract method: can only be used in an abstract class, and it does not have a body. The body is provided by the subclass (inherited from).

What is the difference between class and interface in java?

What are the similarities between interfaces and classes?

Similarities between class and interface:

Class and Interface both are used to create new reference types.
An interface is syntactically similar to the class.
The members of a class can be private, public or protected and the members of an interface are always public.
A class can can extend only one class.

How can we use abstract class and interface together in Java?

Interface contains only abstract methods that can’t be instantiated and it is declared by keyword interface. A class that is declared with the abstract keyword is known as an abstract class in Java.

Why We Need interface if we have abstract class in Java?

Abstract classes provide a simple and easy way to version our components. If we want to provide common, implemented functionality among all implementations of our component, use an abstract class. Abstract classes allow us to partially implement our class, whereas interfaces contain no implementation for any members.