How to Call a Class in Java

Learning how to code in Java is an exciting journey, but it can be overwhelming at times. One of the fundamental concepts of object-oriented programming is classes, which are used to create objects. In this article, we will explore how to call a class in Java and provide step-by-step guidance to help you understand the process.

Table of Contents

Understanding Classes in Java

Before we dive into how to call a class in Java, let’s first understand what classes are. A class is a blueprint or a template for creating objects. It contains variables, methods, and constructors, which are used to define the object’s behavior and properties.

In Java, classes are defined using the keyword "class," followed by the class’s name. Here’s an example of a simple class in Java:

public class MyClass {
   int x = 5;

   public void printX() {
      System.out.println(x);
   }
}

In this example, we have defined a class named "MyClass" that has a variable "x" with a value of 5 and a method "printX" that prints the value of "x" to the console.

Calling a Class in Java

Now that we have a basic understanding of what classes are let’s see how to call a class in Java. Calling a class is the process of creating an object of the class and accessing its properties and methods.

To call a class in Java, we need to follow these steps:

Step 1: Create an Object of the Class

To create an object of a class, we use the "new" keyword followed by the class name and parentheses. Here’s an example:

MyClass obj = new MyClass();

In this example, we have created an object of the class "MyClass" and assigned it to a variable "obj."

Step 2: Access the Class Properties

Once we have created an object of the class, we can access its properties using the dot notation. Here’s an example:

MyClass obj = new MyClass();
int x = obj.x;

In this example, we have accessed the variable "x" of the "MyClass" object and assigned it to a variable named "x."

Step 3: Call the Class Methods

Similarly, we can call the class methods using the dot notation. Here’s an example:

MyClass obj = new MyClass();
obj.printX();

In this example, we have called the "printX" method of the "MyClass" object.

Example Program

Let’s see a complete example program that demonstrates how to call a class in Java:

public class Main {
   public static void main(String[] args) {
      MyClass obj = new MyClass();
      int x = obj.x;
      obj.printX();
   }
}

class MyClass {
   int x = 5;

   public void printX() {
      System.out.println(x);
   }
}

In this example, we have created a class named "MyClass" with a variable "x" and a method "printX." We have also created a main method in the "Main" class, where we have called the "MyClass" object, accessed its variable "x," and called its method "printX."

Conclusion

In this article, we have explored how to call a class in Java. We have learned that calling a class involves creating an object of the class and accessing its properties and methods. We have also seen a complete example program that demonstrates how to call a class in Java.

Learning Java can be challenging, but with practice and patience, you can master it. Keep exploring and experimenting with Java, and don’t forget to have fun along the way. Happy coding!

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