Abstract Class vs Interface – Difference and Comparison

What is Abstract Class?

An Abstract class is referred to as the class described with an Abstract keyword. The summation of common subclasses includes at least one Abstract method.

An abstract class is a template used to store useful programming data methods and members. In Java Instrumentation, Abstract Class is not possible directly but Abstract Class can be informed of subclasses.

Abstract Class provides developers with options for hiding the code execution, which helps to carry out the data abstraction process efficiently. It also minimizes the time for coding. Abstract methods are considered a good way to avoid code duplication.

For using an abstract class in Java there are certain rules to be followed.

  1. When declaring an abstract class it is important to have an Abstract keyword.
  2. To carry out Abstract Class in Java instrumentation at least one Abstract method is required, one cannot have an Abstract class directly.
  3. In the Abstract class, all final methods should be included.
  4. Static and constructor methods should be included in Abstract Class.

An abstract class is considered important as it helps in writing short-length coats and also reduces the chances of repetition of code the showing reusability of code.

What is Interface?

Interfaces are called blueprints and are a tool for representing them in classes. Abstract classes and Interface cannot have different variables and methods. But methods used in interface are abstract by default.

This Interface helps to understand what an Abstract Class is supposed to do. The Interface has a collection of different methods that the class can apply. The Interface is used for attaining Abstraction. The Interface has several provisions that are not supported in Abstract classes.

The Interface is used for loose coupling, where components are weekly related to each other. The interface is mainly used for several Java provisions and abstractions.

The main property of Java Interfaces are

  1. Abstract keyword is not required when declaring the interface. It is considered completely Abstract.
  2. For every abstract method, each interface is also considered Abstract and there is no need for abstract keywords required.
  3. Each interface method is considered public.

The advantage of Java Interfaces is that they can be used for different data abstraction methods and also supports many functions in Java.

Difference Between Abstract Class and Interface

  1. An Abstract class is also called a base class, which defines all the functions and members of the class, where the Interface is considered as a tool to specify the functionality of the Abstract class.
  2. Abstract classes can have data fields and constants, whereas Interfaces cannot have data fields.
  3. Abstract Class is considered as the superclass whereas Interface is considered as a subclass.
  4. Abstract Class has an access modifier whereas Interface does not have any access modifier and everything is assumed to be a public modifier.
  5. In an Abstract class, full abstraction is unavailable, but an Interface can provide full abstraction.

Comparison Between Abstract Class and Interface

Parameters Of Comparison Abstract ClassInterface
DefinitionSummation of different classes that include at least one Abstract method.The interface is the blueprint tool used for representing in class.
Access ModifierAn Abstract Class has access modifiers used for setting accessibility of classes and methods and other members.The interface abstains access modifiers and everything is within and presumed to be a public modifier.
Data FieldsAn Abstract Class can have a data field.The Interface cannot have data fields.
Defining FieldsUsers in the Abstract class can define both fields and constant.Users in the interface cannot define any fields.
Variable TypeIn Abstract class, it can have final, non-final, static, and nonstatic variables.The Interface can have final and static variables.


  1. https://dl.acm.org/doi/abs/10.1145/1040305.1040314
  2. https://link.springer.com/content/pdf/10.1007/978-1-4302-0140-3_12.pdf