What is Abstract Class ?

• Abstract is a keyword that is use with class and method. In abstract class we can define both abstract and concrete method.
• If a class contains any abstract method then class must be abstract.
• If a class contains any abstract method then we have to implement it in the subclass.
• Object of abstract class can't be created.
• To create the object of abstract class, programmer should make use of concrete class. A class which provides implementation to all the abstract method which are present inside abstract class with the help of extends keyword is known as concrete class.

                     

 Example:

             public abstract class I20

          {

               abstract void Wheels();

               abstract void Sunroof();

          }    

            public class Asta extends I20{

            void Wheels()

        {

           System.out.println("Wheels: Alloyed wheels" );

        }

          void Sunroof()

       {

           System.out.prinln("SunRoof: Not Available");

       }

   }

          public class Showroom

     {

          public static void main (String args[]){

          I20 i = new Asta();

          i.Wheels();

          i.SunRoof();

    }

}