Explain the differences between abstract classes and interfaces in Java, and when would you use one over the other?

Explaining the Differences Between Abstract Classes and Interfaces in Java

Abstract classes and interfaces are both important concepts in Java programming, but they serve different purposes. Let's dive into the key differences between them:

Abstract Classes:

An abstract class in Java is a class that cannot be instantiated on its own, meaning you cannot create an object of an abstract class. Abstract classes can have abstract methods (methods without a body) as well as concrete methods. Subclasses that extend an abstract class must implement all the abstract methods defined in the abstract class.

Interfaces:

Interfaces in Java are similar to abstract classes but with some crucial differences. An interface can only have abstract methods (methods without a body) and cannot have any concrete methods. Classes achieve interface functionality by implementing the interface and providing definitions for its abstract methods.

When to Use Abstract Classes vs. Interfaces:

Choosing between abstract classes and interfaces depends on the specific use case:

• Use Abstract Classes when: You want to provide default functionality in your base class and require subclasses to implement specific methods while sharing some common behavior.
• Use Interfaces when: You want to define a contract for classes to implement certain methods without providing any implementation details. Interfaces are useful for achieving multiple inheritances in Java.

It's important to note that a class can implement multiple interfaces but can only extend one abstract class.

Focus Keyword: Java Abstract Classes vs. Interfaces