Abstract Classes and Methods in Object Oriented Programming

By Dharani Prasanna, IBM India

Abstract Class:  Classes which contain one or more abstract methods or abstract properties, such methods or properties do not provide implementation. These abstract methods or properties are implemented in the derived classes (Sub-classes).  

Abstract classes does not create any instances to that class objects  

Use of Abstract class:

We can define some common functionalities in Abstract class (Super-class) and those can be used in derived classes (Sub classes).  

Step-by-Step Approach to create Abstract classes and Methods  

TCode: SE24  

Enter the name of class as 'Z_DEMO_ABS_CLASS' and press Create Button  

A pop-up window is displayed, then select "Class" radio button and

Press enter  

It will go to the next screen.  

Here you enter the Description of the class and then select "Abstract" from Instantiation Drop down list to define the class an abstract class,

Then click on save  button  

Go to the "Attributes" tab,  

Enter the Attribute name, Level, Visibility, Type and Description as shown in the screen shot.

Go to Methods tab,

Enter Method name, Level, Visibility and Description as shown in the below screen shot

Double click on the Method name "AREA"; it goes to method Implementation screen.

Go to Menu path, then Goto -> Method definition

Pop-up window is displayed. It gives complete information of the method

Click here to continue...