18.11.2023
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Beğenme
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Görüntülenme
An abstract class in Java is one that is intended to be subclassed by other classes and cannot be instantiated on its own. It can have concrete methods, abstract methods, or a mix of both; it acts as a model for other classes.
Abstract Keyword:
The abstract keyword is used to declare an abstract class. Abstract classes may have abstract methods (methods without a body) as well as concrete methods (methods with a body).
Abstract Methods:
Abstract classes can have abstract methods, which are declared without a body and are meant to be implemented by the subclasses.
Subclassing:
When you extend an abstract class, you must either provide concrete implementations for all the abstract methods in the subclass or declare the subclass as abstract.
Constructor:
Abstract classes can have constructors, and they are invoked when a subclass object is created. However, abstract classes cannot be instantiated directly.
Usage:
Abstract classes are useful when you want to provide a common interface or functionality that should be shared among multiple related classes.
In this example, Shape is an abstract class with an abstract method draw() and a concrete method display(). The Circle class extends Shape and provides a concrete implementation of the draw() method. The display() method is inherited from the Shape class.
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