An abstract class in Java is declared as abstract and may include abstract methods, but cannot be instantiated. It can be subclassed, allowing other classes, such as graphic objects like triangle, circle, and line, to inherit from it. This structure enables the creation of a hierarchy of graphic objects based on the abstract class.

2. ABSTRACT CLASS IN JAVA
• AN ABSTRACT CLASS IS A CLASS THAT IS DECLARED ABSTRACT – IT MAY OR
MAY NOT INCLUDE ABSTRACT METHOD.
• ABSTRACT CLASSES CANNOT BE INSTANTIATED, BUT THEY CAN BE
SUBCLASSED.

3. ABSTRACT CLASS
• GRAPHIC OBJECT LIKE
• TRIANGLE
• CIRCLE
• LINE
• BEZIER

4. ABSTRACT CLASS
• FIRST YOU DECLARE AN ABSTRACT CLASS THEN INHERIT THESE CLASSES
FROM GRAPHIC OBJECTS.