An abstract class is a type of class that cannot be instantiated and can only be used as a parent class. Abstract classes are typically used to define common properties and methods, but the specific implementation must be completed in the child classes.
An abstract method is a method without a body, only the method declaration. Subclasses must implement all abstract methods, otherwise the subclass must also be declared as abstract.
The existence of abstract classes and methods can enhance the flexibility and scalability of code by allowing the parent class to define some common methods and attributes, while leaving the specific implementation to be completed by the child class.
In Java, the keyword “abstract” is used to declare abstract classes and abstract methods. Abstract classes must contain at least one abstract method, and abstract methods can only exist in abstract classes.
