How to Create Variables in Java (with Images)

2025 Author: Jason Gerald | [email protected]. Last modified: 2025-01-10 13:41

Variables are one of the most important concepts in computer programming. Variables store information such as letters, numbers, words, sentences, true/false, and more. This article is an introduction to how to use variables in Java. This article is not intended as a complete guide, but as a stepping stone into the world of computer programming.

Step

Step 1. Create a simple Java program

The example provided here is named Halo.java:

public class Hello { public static void main(String args) { System.out.println("Hello World!");

Step 2. Scroll to where you want to insert the variable

Remember: if you place a variable in the main class, you can refer to it anywhere. Select the type of variable you need.

• Integer data type: used to store integer values like 3, 4, -34 etc.

  • bytes
  • short
  • int
  • long

• Floating Point data type: used to store numbers that contain fractional parts such as 3, 479

  • float
  • double

  • Character data type (Character): used to store characters like 's', 'r', 'g', 'f' etc.

    char

  • Boolean data type: can store one of two values: true and false

    boolean

  • Reference data type (Reference): used to store references to objects

    • Array Type
    • Object Types like String

• Create a variable. The following is an example of how to create and define values for each type.

  

  • int someNumber = 0;

    

  • double someDouble = 635.29;

    

  • float someDecimal = 4.43f;

    

  • boolean trueFalse = true;

    

  • String someSentence = "My dog ate a toy";

    

  • char someChar = 'f';

    

• Know how it works. Basically, the trick is "type name = value".

  

• Protect the variable from being edited again, optionally, by adding "final type name" between the brackets on the second line of your code (public static void main).

  

  final int someNumber = 35; Adding 'final' here means that the variable 'someNumber' is immutable

Tips

• Each variable in a program must have a unique name or you will run into errors.
• In Java, all command lines must end with;
• Different variables can have the same name under certain conditions. For example, a variable in a method can have the same name as the example variable name.