An abstract class is a Class that cannot be instantiated. It may have abstract
methods. Abstract methods are methods without implementation in the class specification. Subclasses that inherit the abstract class need to provide implementation to the abstract method.
Steps to create an Abstract class
Enable UML mode.
Add new class by clicking on the Add New Class button.
Give a name to the class.
Choose Abstract in the Modifier drop down.
We cannot create objects of Abstract class. We can, however, subclass an abstract class and create a concrete class that can be used in the flow chart or the application.
To create an abstract method.
Right-click on the class >> Edit Members
Click on the new method button.
Click on the checkbox Abstract to make the method abstract.