Abstract Class vs. Interface

An abstract class is described with both the abstract keyword in Java. It could contain both abstract & non-abstract techniques (method with the body). The act of hiding technical details from the user and showing only functionality is known as abstraction. A derived class procedure is declared inside the class description using a pure query need.

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cAbstract Class Vs. Interface

The abstract class is composed that would be designed to be explicitly used as a class name. In an abstract class, at least one pure virtual function exists. A derived class function is declared in the class description by employing an advanced query need (= 0) in the definition of a virtual function call. The abstract class is among that is described well with the abstract keywords in Java. It might include abstract and non-abstract approaches (method with the body).


Let’s first comprehend abstraction in Java before understanding the Java abstract class.


The technique of hiding technical aspects from the user and showing only functionality is known as abstraction.


In another manner, it displays only the necessities to the user while concealing the internal nuances, like sending SMS messages, in which you enter the content and send the message. You are entirely oblivious of the internal information transmission processing.


Abstraction concentrates on what an entity does rather than what it does it.

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Techniques for Getting Abstraction

Through Java, abstraction can be achieved in two different methods.

  • class abstraction (0 to 100 percent)
  • connection (100 percent).


The abstract class in Java

A declared abstract class that has been considered abstract. It can support both abstract & non-abstract methods. It has to be expanded, and its technique put into action. It cannot be created.


Important Reminders

  • The abstract keyword must be used to declare an abstract class.
  • It can support both abstract & non-abstract methods.
  • It cannot be created.
  • It can also have a constructor and static methods.
  • This can have final methods, which force the subclass not to change the method body.
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Abstract Method in Java

The abstract method is something that is declared abstract but lacks implementation.

Discovering the application of said Abstract class Throughout this example, Shape is the abstract class, as well as the Rectangular & Circle classes, execute it. We don’t know much about the conforming class (which would be hidden from the end-user) or the factory function, which returns an instance of it. A factory design pattern returns the instance of a class. The factory method is described further down the road.


Templates in the Abstract class

In Java, an abstract class is a template that keeps the member functions and functions that we utilize in our programs. In Java, abstraction shields the user from sophisticated code implementations while delivering helpful information.

In Java, we cannot explicitly instantiate the abstract class. We can instead subclass the base model. When we utilize a base model as just a subclass, the method implementation of the abstract class is made accessible to all of its classes.

Moving on, we shall discover all of the excellent advantages of the abstract data type in Java. A design pattern would deliver the instance of a class. The factory method will be covered later.


Abstract Class Template Characteristics

The abstract class from Java allows the best technique to execute the data abstraction process by enabling developers to hide the code implementation. It also provides the end-user with a template that describes the methods used.

  • Coupling, Loose – Abstraction in Java promotes loose coupling by exponentially reducing dependencies.
  • Reusability of Code – Using an abstract class saves time in the code. We can invoke the abstract method anywhere it is required. The abstract class eliminates the need to rewrite the same code.
  • Abstraction – Data abstraction in Java allows developers to hide code complexities from the end-user by limiting the project’s total characteristics to simply the necessary components.
  • Using Dynamic Resolution – With dynamic method resolution support, developers can handle various problems with a single abstract method.

Before we proceed, let’s first learn how and where to declare an abstract class.

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Rules for Declaring an Abstract Class

The following are the main rules to remember when utilizing an abstract class using Java:

  • When declaring an abstract class in Java, the term “abstract” is required.
  • Abstract classes could be explicitly instantiated.
  • There must be at minimum one abstract method in an abstract class.
  • Final methods are included in an abstract class.
  • Non-abstract methods may be included in an abstract class.
  • Constructors & static methods can be found in an abstract class.


Benefits of Abstract Classes

  • The abstract class for Java is quite helpful for writing shorter code.
  • Java abstraction prevents code duplication.
  • Abstract classes allow for code reuse.
  • Internal code implementation changes are made without affecting classes.
  • Let us now look at the significant downsides of using an abstract class with Java.

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The Drawbacks of Abstract Classes

  • Abstraction in Java is costly since you must handle scenarios and situations that are not always necessary.
  • In the case of RDBMS, object-relational impedance mismatch
  • Object-relational mappings occur in frameworks such as hibernate.
  • So, those were the main benefits and drawbacks of an abstract class for Java.

This brings us to the end of this “Abstract Class using Java” topic. We hope you liked learning about the fundamental concepts behind abstractions in Java and the difference between abstract class and Interface.

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What exactly is an interface in Java?

An interface in Java specifies a class’s behavior by giving an abstract type. This technology supports abstraction, polymorphic and multiple inheritances, and fundamental Java ideas. In Java, interfaces are used to accomplish abstraction. A Java class may implement an interface using the implements keyword. In general, an interface is a container that retains the signatures of methods executed in the line of code. It increases Abstraction levels.

Following the basic introduction to Interface for Java, we now will investigate why we’re doing this and why it is preferable to the traditional method to use an abstract class.


Java Interface Required

So, we need a Java interface for the following reasons:

  • Total Isolation
  • Inheritance from Multiple Parents
  • Loose-Coupling

Total Isolation – The key principle of Object-Oriented programming approaches is an abstraction. The method signature is the only thing an interface stores, not the method specification. Method Signatures allow an Interface to achieve complete abstraction by concealing the achieved status from the user.

Inheritance from Multiple Parents – Numerous inheritances are impossible without Interface because the traditional method of adopting multiple parent classes leads to substantial uncertainty. The Diamond problem refers to this form of uncertainty. This is fixed by using Interface.

Loose Coupling – Coupling refers to a class’s reliance on another. As a result, when we use an interface, we declare the method and the signature individually. As a result, all methods & classes are self-contained and preserve Loose Coupling.

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Nesting Interface in Java

The Nesting Interface technique is used to overcome namespace concerns by grouping similar interfaces or relevant interfaces with class. As a result, this example relies based on nested interfaces. We are attempting to print the first ‘n’ prime numbers using interface layering.

An interface is defined as an abstract type in Java language that is used to govern the functionality of a class. An interface seems to be a class blueprint in Java. Either static variables or abstract methods are present in a Java interface. The Interface is a method of obtaining abstraction in Java. Only abstraction methods, not method bodies, are permitted in the Java interface. It is used in Java to achieve abstractions and multiple inheritances. To look at it differently, interfaces are capable of having abstract variables and methods. Getting a functioning body is against the law. The Java interface also represents the IS-A relationship. 

An interface, like a class, can still have methods & variables. However, the methods stated in an interface are always abstract (only method signature, nobody).

  • Interfaces define whatever a class must accomplish rather than how it must do it. It is the course’s plan.
  • An interface is concerned with abilities, such as mobility, and any class that inherits Player should be competent of (and so must express) moving (). Consequently, it specifies a suite of procedures for the type to follow.
  • An abstract class implements an interaction but does not have a method body for all the Interface’s functionalities.
  • A Java library is an example of a Comparator Interface. If a subclass satisfies this Interface, it can be used.


What is the purpose of an interface?

  • It is employed to achieve complete abstraction.
  • Because Java doesn’t allow multiple inherited riches in the framework of classes, various windfalls can be obtained through an interface.
  • It works well for loose coupling as well.
  • Abstraction is implemented through interfaces. Why then do we need interfaces now that we already have abstract classes?
  • This is because abstract classes can have non-final variables, whereas interface variables are final, public, and static.


The Benefits of Java Interfaces

The following are the benefits of using interfaces in Java:

  • We can accomplish implementation security without worrying about the implementation component.
  • Multiple inheritances are not permitted in Java; however, you can utilize an interface that enables advantage of it because you could implement over one Interface.


Java Interface Disadvantages

  • In real-world projects, interfaces are used extensively or just not.
  • The use of Interfaces can slow down execution.
  • These are some of the drawbacks of using an interface in Java.
  • We have now reached the end of an “Interface in Java” article. We hope you liked learning about the fundamental concepts of Java interfaces. 
  • The Interface is just one of many essential ideas in Java Object-Oriented Programming. It is strongly advised to read all of the Object-Oriented Basic Programming in Java for a good understanding of their interdependence.

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key aspects of Interface

We cannot construct an instance of the Interface (it cannot be instantiated), but we can make a reference to it that relates to the Way of its implementation class.

  • A class could implement many interfaces.
  • An interface can communicate with another interface or interfaces (more than one Interface).
  • A class that interfaces the Interface should implement all of the Interface’s methods.
  • All of the approaches are open to the public and abstract. Furthermore, all fields are accessible, static, and final.
  • It is employed to achieve multiple inheritances.
  • Its purpose is to attain flexible coupling.

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End note –

An abstract class is described with both the abstract keyword in Java. It could contain both abstract & non-abstract techniques (method with the body). The act of hiding technical details from the user and showing only functionality is known as abstraction. A derived class procedure is declared inside the class description using a pure query need. The abstract class is a categorical variable that enables developers to carry out the data abstraction procedure by hiding the code implementations from the end-user. Learn at 3RI Technologies.


Declaring an abstract class in Java was needed, and such a class must contain at least a single abstract method. Abstract class vs interface java by lowering dependencies exponentially, abstraction in Java encourages loose coupling. An interface is a type of program inside the Java programming language. An abstract type is used to describe the behavior of such a class. This technology supports the Java concepts of abstraction, polymorphism, and multiple inheritances. An interface is a structure that defines the signatures of methods that will be called in a line of code.

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