An abstract type is a type in a nominative type system which cannot be instantiated directly. Abstract types are also known as existential types. An abstract type may provide no implementation, or an incomplete implementation. The object oriented form of abstract types are known as abstract base classes or simply abstract classes.
Syntax
abstract class class_name {
//abstract method_name
}
Abstract Class Example Program
abstract class One {
abstract void methodTwo();
void disp() {
System.out.println("I am inside a concrete method.");
}
}
class Two extends One {
void display() {
System.out.println("I am inside extended class B.");
}
}
class AbstractClassDemo {
public static void main(String args[]) {
Two obj = new Two();
obj.display();
obj.disp();
}
}
Sample Output
Output is:
I am inside extended class B.
I am inside a concrete method.
