When And How to Use Abstract Class and Interface

The major aspects of the Java software design language are abstract-classes and the interfaces. However, both of the building blocks are mainly utilized for the abstraction, they’re quite dissimilar from each other; would not be utilized interchangeably. The interface would be utilized to describe a contracted behavior; it would also be acting out as a contract among the 2 networks to keep interacting whereas an abstract-class is typically utilized to describe defaulted behavior only for the subclasses, so it indicates that the entire child-classes would act the similar functionality. In this article, we will discuss when and how to use abstract class and interface to learn Java and other OOP.

Abstract Class in Java

In any of the software designing language, abstraction refers to hide the inappropriate detailing from the consumer to keep focusing merely on some important details on account to enhance effectiveness by this means reduce the complexity. In Java, the process of abstraction can be attained by making use of abstract classes. In general, abstract class detects the mutual features of the subclasses and it might or mightn’t encompass any of the abstract methodologies. It won’t be instantiated; however, it would be solely utilized as a superclass concerning its subclasses.

Abstract-class is such a class which is acknowledged as abstract; it might or mightn’t encompass abstract methodologies. The abstract class might occupy statistic domains along with statistic methodologies. As soon as abstract-class is sub-classed, that subclass typically offers executions for the entire abstract methodologies in its main class. On the other side, in case it won’t; the subclass should be acknowledged as abstract.

When And How To Use An Abstract Class

  • Abstract-class is a great selection in case a person is utilizing the idea of inheritance as it offers a shared base class execution to derive the classes.
  • Abstract-class is a great thing if a person wants to state the members of non-public. Whereas in the interface, the entire methodologies should be public.
  • If a person desire to introduce the newest methodologies in upcoming time; abstract-class would be a better selection. The reason is if a person introduces the newest tactics to the interface, then the entire classes which were previously executed that interface would be modified to execute the newest methodology.
  • If a person is interested to generate numerous versions of the component then they should generate abstract-class. Abstract-classes offer a simplest and the easiest way to style the components. Once you update the base-class, the entire inherited classes were spontaneously updated along with the modification. On the other side, interfaces would not be generated if they were created. In case if there is a need for the newest version of the interface, then the entirely new interface should be created.
  • Abstract-classes are the ones who own the benefit to allow enhanced forwarded compatibility. As soon as consumers utilize the interface then we are not allowed to make any changes in it; on the other sider if consumers utilize the abstract-class, still we would add the behavior without break remaining codes.
  • If a person is interested to offer common, executed functionality in the entire operations of the component then they must make use of the abstract class. In general, abstract-classes basically let the person execute the class to some extent, while an interface comprises not the execution for the members.

Abstract Methods in Java

  • Abstract-methods are such methodologies which are without implementation. They don’t encompass any of the methodological statement.
  • Child classes of such abstract-class should offer the execution of such inherited methods of abstract.
  • The abstract methodology is declaring with the abstract keyword.
  • The statement of the abstract methodology should be ended with a semi-colon ;

Interface in Java

The interface is only the statement of such methodologies of the object; it is not the execution. In the interface, it is defining what type of functionality the object would be performed. Such operations are defining by classes which are implementing an interface. Interfaces make an association among the outside world and the class, and such association is imposed at building time by the compiler. Other ways of attaining abstraction in Java is achieved by making use of the interfaces. The interface is a bunch of abstract methodologies; it would not have any existing methods, contrasting to the abstract class. However, contrasting to the abstract class, the interface offers the whole abstraction in Java. It would own both of the variables and methods similar to the class. On the other side, the methodology is declaring in the interface is abstract that is by default.

When And How To Use An Interface

  • In case, the functionality we’re generating would be beneficial throughout the huge range of the dissimilar objects then you should make use of the interface. Abstract-classes must be utilized mainly for the thoroughly relatable objects, although interfaces considered as the ones, which are greatly suitable to provide a shared functionality on account to unrelated the classes.
  • Interfaces seem to be a great selection as soon as we give a thought that A-P-I would not alter a little bit.
  • If a person designs a small and brief functionality then they should make use of the interfaces. In case, we’re planning to design a big well-designed unit then we should utilize the abstract class.

Implementing Interfaces

The class that implements the interface would be assumed like a class which assigns a contract. It refers to the fact that classes agree to act out the precise behaviours of Interface. Except the class is stated as the abstract then it must be acted out the entire behaviours of Interface. On account to execute the Interface in Java, a class utilizes the implemented keyword. Such implemented keyword look like in the class statement once extended portion of the statement.


Interface and Abstract-class are the most significant characteristic of Java. These aspects assist a person to attain the Abstraction in Java. In the Java, interfaces and Abstract-classes are considered as the essential building blocks because both of them are utilized to execute the important ideas of the Object-Oriented-Programming i.e. Abstraction. In the meanwhile, these two are utilized for the Abstraction, though they are not similar ones as well as one would not utilize them interchangeably. However, an individual can experience from an IT Bootcamp to get hands-on it for better results.