Abstract Class in Java

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An abstract class is a class that cannot be instantiated and can only be used as a superclass for other classes. Abstract classes can contain both abstract and non-abstract methods, as well as instance variables. In this tutorial, we will provide an example of how to create and use an abstract class in Java.

Creating an Abstract Class in Java

To create an abstract class in Java, you need to use the abstract keyword in the class declaration. Here is an example of an abstract class:

public abstract class Animal {
   private String name;

   public Animal(String name) {
      this.name = name;
   }

   public String getName() {
      return name;
   }

   public abstract void makeSound();
}

In this example, we have created an abstract class called Animal. The Animal class has an instance variable called name and a constructor that takes a name parameter. It also has a getName method that returns the name of the animal.

The Animal class also has an abstract method called makeSound. Abstract methods are defined using the abstract keyword and do not have an implementation. Any class that extends the Animal class must provide an implementation for the makeSound method.

Using an Abstract Class in Java

To use an abstract class in Java, you need to create a subclass that extends the abstract class and provides an implementation for any abstract methods. Here is an example of a subclass that extends the Animal class:

public class Dog extends Animal {
   public Dog(String name) {
      super(name);
   }

   public void makeSound() {
      System.out.println("Woof!");
   }
}

In this example, we have created a subclass of the Animal class called Dog. The Dog class has a constructor that takes a name parameter and passes it to the Animal constructor using the super keyword.

The Dog class also provides an implementation for the makeSound method, which prints “Woof!” to the console.

Also, see the example code JavaExamples_NoteArena in our GitHub repository. See complete examples in our GitHub repositories.

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