What is the difference between abstract classes and concrete classes in Java?

What is the difference between abstract classes and concrete classes in Java?

Abstract classes cannot be instantiated and may contain abstract methods, while concrete classes can be instantiated and provide implementations for all methods.

Can you give me an example of an abstract class in Java?

Sure! Here's a simple example:

abstract class Animal {
    abstract void sound();
}

class Dog extends Animal {
    void sound() {
        System.out.println("Bark");
    }
}

What about concrete classes? Can you show me an example?

Absolutely! Here's an example of a concrete class:

class Car {
    void drive() {
        System.out.println("Driving");
    }
}

When should I use an abstract class instead of an interface?

Use an abstract class when you want to share code among closely related classes, while interfaces are better for defining a contract for unrelated classes.