Abstract class in Java

Abstract Class in Java

James Gosling designed Java in the year 1995 at Sun Microsystem. It has various features, including portability, reliability, and platform support.

It has various applications, including the internet, mobile gaming, and business organizations. Platforms include Java Platform, Micro Edition, Enterprise Edition Java Platform, and Standard Edition Java Platform.

What is Abstract class?

Constructor is present in the abstract class, which is accessed by subclass using the super keyword. In Java, whenever a class is defined with the keyword Abstract that class is known as an Abstract Class. The implementation details are hidden in the abstract class, while the functionality is only displayed to the user.

For example, accessing the T.V remote to increase the volume, the user does not know the internal working process. Only the operation is done. The two main topics in the abstract class are Interface and Abstract class.

Features of Abstract Class

1. Abstract class can’t be created in instance.

2. Constructors are created in the abstract class.

3. Creating an abstract class where the abstract method is not present inside the class.

4. In an abstract class, the object is not created.

5. In the abstract class, a static method is created.

6. Keyword abstract is mandatory to create an abstract class.

7. Both abstract and non-abstract class is presented.

8. The final method is present in the abstract class.

9. The implementations are created for all abstract methods to extract the abstract class.

Abstract classes disadvantages

1. The several disadvantages of abstract classes are,

2. It is expensive to handle cases and situations

3. Tough to create the class in Java.

4. Multiple Inheritances are not created in abstract class

5. One super class only inherits the class; hence the effect of abstract class is reduced.

6. Complexity occurs in Abstract classes

Abstract class Programming

The abstract class used in programming language includes Java, C hash ++, an object-oriented language.

The abstract class and method play a vital role in the abstraction class in Java.

Java Interfaces

a) Java abstract class is obtained through an interface. In interfaces, the object is not created like the java abstract class.

b) The implementing class creates a body for the interface.

c) The methods in an interface are public and abstract.

d) Attributes are defined based on final, static, and public.

e) It doesn’t contain a constructor.

f) The interface is divided into multiple interfaces.

g) The difference between interface and java abstract class is that java abstract allows creating functionality where subclasses can override. The interface can create functionality that it won’t implement.

h) The abstract class may contain static, non-static, final, and non-final variables. It also contains abstract and non-abstract methods. The concept of multiple inheritances is supported here. Extend keyword is used to extract the abstract class. Member classes like private and protected are also present.

i) Unlike abstract classes, the interface contains only the abstract method. The variables used are final and static. The keyword used here is the interface. The concept of multiple inheritances is not supported here. The class members are present in public by default.

j) The abstract provides the user with full code, whereas the interface provides the signature. The abstract class works faster when compared to the interface. The interface working process is slower compared to the abstract class. Access specifier is presented in functions and properties of an abstract class. While in the interface, the access specifier is not presented. Fields and constants are allowed to be present in the abstract class, while it was not allowed in the interface.

Applications of Java

Some familiar apps running in java language are Opera Mini, Spotify, Twitter, Cash app, Think free Office, etc. Widely it is used for Mobile applications, Web-based applications, Desktop-GUI applications, Gaming, Scientific application, etc. The familiar project in Java includes NASAworld wind, Google and Android Operating System, my craft, etc.

The syntax for abstract class is as follows:

// create an abstract class

abstract class Language {

// fields and methods

}

…

// try to create an object Language

// throws an error

Language obj = new Language();

Both regular and abstract methods present in Java are,

abstract class Language {
// abstract method

Summary

Hence, the abstract class, interface, and methods are clearly explained and mentioned in the above article.

abstract void method1();
// regular method
void method2() {
System.out.println("This is regular method");
}
}

The java abstract class and method are presented as follows,

abstract class Language {
// method of abstract class
public void display() {
System.out.println("This is Java Programming");
}
}
class Main extends Language {
public static void main(String[] args) {
// create an object of Main
Main obj = new Main();
// access method of abstract class
// using object of Main class
obj.display();
}
}

Summary

Hence, the abstract class, interface, and methods are clearly explained and mentioned in the above article.