Table of Contents
What is Abstract Class in Java?
An abstract class is a class that contains common behaviour, but cannot be directly instantiated. Instead, an abstract class provides a blueprint for creating instances of its subclasses. Each subclass is free to add its own specific behaviour to the features provided by the abstract class. This enables a single class to be reused in multiple situations, while still maintaining its identity and purpose.
Abstract classes are a special type of class. An abstract class contains member variables and methods that must be defined by all objects that are instances of that class. There are two ways to declare an abstract class: using the keyword abstract and using the keyword final. Using the keyword final is the preferred way to declare an abstract class since it prevents code from being generated that might violate a design smell.
An abstract class is a class that contains methods and variables, but cannot be instantiated. The class is defined, but cannot be used. Abstract classes are used to create subclasses. When you create an abstract class, you are defining the characteristics of a subclass, but the class cannot be used until it is made into a subclass.
What is Interface in Java?
An interface is a set of requirements that must be met to use a class or a group of classes. An interface declares a contract between the implementer of the interface and the client of the interface. The client of the interface must provide the implementer of the interface with the necessary information to meet the requirements of the interface. This information is the implementation details of what is required to meet the requirements of the interface.
An interface in the Java programming language is a set of Juan (body) and methods (verbs) that specify the behaviour and attributes of objects. Java interfaces can be used to define abstract classes. When used as the base for an inheritance, interfaces provide a way for subclasses to override methods and provide their own implementation. This is useful for creating polymorphic behaviour in a Java program, which can be very useful in creating generic classes.
An interface is a contract or set of requirements that define the behaviour or capabilities of a class, module, or module subset. The Java programming language defines interfaces as the contract between an object (a class) and its environment. This means that an interface defines the behaviour or capabilities that a class, package, or module may provide to its environment. This environment may be another class, another package, a static method or field, and so on.
Difference Between Abstract Class and Interface in Java
- An Abstract Class uses both abstract and non-abstract methods, while Interface uses only Abstract methods.
- An abstract class can use Final, Non-Variable, Static and Non-Static Variables whereas an interface can only use final and static variables.
- An abstract class can give the execution of the Interface. On the contrary, Interface can’t give the execution of an abstract class.
- Abstract classes are available for private classes as well whereas Interface is only for the public.
- An Abstract Class can extend other classes and Java interfaces. On the other hand, Interface Can only extend various Java interfaces.
Comparison Between Abstract Class and Interface in Java
|Parameters of Comparison||Abstract Class||Interface|
|Abstract Methods/ Non- Abstract Methods||Both Abstract and Non-Abstract Methods||Only Abstract Methods|
|Variables||Final, Non-Variable, Static and Non-Static Variables||Final Variables and Static Variables|
|Execution||An abstract class can give the execution of the Interface.||Interface can’t give the execution of an abstract class.|
|Availability||Private or protected||Public|
|Different executions||Can extend other classes and Java interfaces.||Can only extend various Java interfaces.|