Can we create object of abstract class in Java
Abstract classes are a fundamental concept in Java that cannot be instantiated on their own. An abstract class is a class that contains abstract methods (methods without a body) that must be overridden by any concrete (non-abstract) subclass.
An abstract class in Java is a class that cannot be instantiated on its own. It provides a blueprint for concrete subclasses, which are classes that extend the abstract class and provide implementations for its abstract methods. Abstract classes are used to define a common interface for a group of related classes, and to provide a base implementation for methods that are common to all subclasses. An abstract class can contain both abstract and concrete methods. Concrete methods are methods that have a body and can be used as-is, while abstract methods are methods that are declared but have no body, and must be overridden by concrete subclasses.
Abstract classes are declared using the abstract keyword, and an abstract method is declared using the abstract keyword in front of the method signature.
In Java, it is not possible to create an object of an abstract class using the new operator. This is because an abstract class is incomplete and cannot be used on its own. Instead, an abstract class serves as a blueprint for concrete subclasses that must provide implementations for the abstract methods.
For example, consider the following abstract class:
abstract class Shape {
abstract void draw();
}
This abstract class defines an abstract method called draw that must be overridden by any concrete subclass. To use the abstract class, you must create a concrete subclass that provides an implementation for the draw method.
class Circle extends Shape {
void draw() {
System.out.println("Drawing a Circle");
}
}
In this example, the Circle class extends the abstract Shape class and provides an implementation for the draw method. Now, you can create an object of the Circle class and call the draw method.
Circle circle = new Circle();
circle.draw();
The output of this code will be:
Drawing a Circle.
Here's another example of an abstract class in Java, along with an explanation of the code and the output.
Main.java
abstract class Animal {
abstract void makeSound();
}
class Dog extends Animal {
void makeSound() {
System.out.println("Woof");
}
}
class Cat extends Animal {
void makeSound() {
System.out.println("Meow");
}
}
public class Main {
public static void main(String[] args) {
Animal dog = new Dog();
Animal cat = new Cat();
dog.makeSound();
cat.makeSound();
}
}
In this example, we have an abstract class called Animal, which has an abstract method called makeSound. We also have two concrete subclasses called Dog and Cat, which both extend Animal and provide implementations for the makeSound method.
In the main method, we create objects of the Dog and Cat classes, and assign them to variables of type Animal. This is because Dog and Cat are both subclasses of Animal, so we can refer to them as Animal objects.
Finally, we call the makeSound method on both objects, and the output of the program is:
Output:
Woof
Meow
This demonstrates the power of abstract classes in Java, as it allows us to define a common interface for a group of related classes, and use objects of these classes interchangeably.
You can say, no, it is not possible to create an object of an abstract class in Java. An abstract class is a class that cannot be instantiated on its own, but serves as a blueprint for concrete subclasses. These concrete subclasses must provide implementations for the abstract methods defined in the abstract class.
An abstract class is useful for defining a common interface for a group of related classes, and for implementing methods that are common to all subclasses. However, because an abstract class is incomplete, it cannot be used on its own.
To use an abstract class, you must create a concrete subclass that extends the abstract class and provides implementations for the abstract methods. This concrete subclass can then be instantiated using the new operator, and its methods can be called. you cannot create an object of an abstract class in Java, but you can create objects of concrete subclasses that extend the abstract class and provide implementations for its abstract methods.
In conclusion, it is not possible to create an object of an abstract class in Java. Instead, an abstract class serves as a blueprint for concrete subclasses that must provide implementations for the abstract methods. By doing so, abstract classes provide a way to define a common interface for a group of related classes.