The document discusses the concept of abstract classes in Java, explaining that they are declared with the 'abstract' keyword and can contain both defined and undefined methods. It provides the syntax for declaring an abstract class and includes an example with a class named 'graphicdesign' that has an abstract method 'draw'.

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Abstract Class in Java
AbstractClassin Java - Abstract classis declare withabstractkeyworditcontainsome defined
methodsandsome undefinedmethods.
Syntax to declare abstract class
abstract classclass_name
{
........
........
}
publicabstractclass GraphicDesign
{
// declare fields
// declare nonabstractmethods
abstract voiddraw();
}