Can you explain what the use of the abstract keyword means in programming?

The keyword abstract in programming, for example in Java, is used to declare abstract classes and methods.

• An abstract class is a class that cannot be instantiated directly and serves as a template for other classes.
• An abstract method is a method without an implementation that must be overridden by subclasses.

This allows creating a common interface and basic functionality, leaving implementation details to subclasses.

Example:

abstract class Animal {
    abstract void makeSound(); // abstract method

    void breathe() {
        System.out.println("Breathing");
    }
}

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

Here, Animal is an abstract class, and makeSound is an abstract method that must be implemented in the Dog class.