What is the difference between an abstract class and an interface in Java, and when would you choose to use one over the other?

Difference between Abstract Class and Interface in Java

When it comes to Java programming, understanding the dissimilarities between an abstract class and an interface is crucial. Both serve as templates for creating classes, but they have distinct features.

Abstract Class:

• An abstract class can have concrete methods along with abstract methods.
• It can have instance variables.
• It cannot support multiple inheritances.
• Used when you need to provide a partial implementation of a class.

Interface:

• An interface only contains method signatures and constants.
• It cannot have method implementations or instance variables.
• Supports multiple inheritances.
• Used when you want to define a contract for a class.

When to Choose:

Choose an abstract class when you want to create a base class with some default behavior that can be inherited by subclasses. Use an interface when you want to enforce a contract for classes to implement specific methods.

Ultimately, the decision on whether to use an abstract class or an interface depends on the specific requirements of the program and the design goals.

For more information on the distinction between abstract classes and interfaces, explore our comprehensive guide on Java programming topics.