How Do You Declare an Integer Data Type in Java?


Larry Thompson

In Java, declaring an integer data type is a fundamental concept that every programmer must understand. Integers are whole numbers that can be positive, negative, or zero.

They are commonly used for counting, indexing, and performing mathematical calculations. In this tutorial, we will explore the different ways to declare an integer variable in Java and provide examples for better understanding.

Declaring an Integer Variable

To declare an integer variable in Java, you need to specify its data type followed by the variable name. Here’s the basic syntax:

int myNumber;

The above code declares a variable named myNumber of type int. The int keyword represents the integer data type in Java.

Initializing an Integer Variable

An uninitialized variable holds a default value depending on its data type. For integers, the default value is 0. However, it’s good practice to initialize variables explicitly to avoid any unexpected behavior or errors.

You can initialize an integer variable at the time of declaration using the assignment operator (=). Here’s an example:

int myNumber = 42;

The above code declares a variable named myNumber of type int and initializes it with a value of 42.

Different Ways to Declare and Initialize Integers

In addition to the basic syntax mentioned above, there are other ways to declare and initialize integer variables in Java:

  • Type Inference (Java 10+)

    If you are using Java 10 or above, you can use the var keyword for type inference. Type inference allows the compiler to determine the data type based on the assigned value.

    Here’s an example:

    var myNumber = 42;

    The above code declares a variable named myNumber using type inference. The compiler infers that the variable is of type int based on the assigned value.

  • Multiple Variables

    You can declare and initialize multiple integer variables in a single line by separating them with commas. Here’s an example:

    int x = 10, y = 20, z = 30;

    The above code declares three variables: x, y, and z, all of type int, and initializes them with values.

  • Floating-Point Literals (Widening Conversion)

    You can assign a floating-point literal to an integer variable, and Java will perform a widening conversion automatically. Here’s an example:

    int myNumber = 3.14;

    The above code assigns a floating-point literal value of 3.14 to the integer variable named myNumber. Java automatically converts it to an integer by truncating the decimal part.

  • Naming Conventions for Integer Variables

    To write clean and readable code, it’s important to follow the naming conventions for variables. Here are some rules to consider when naming integer variables:

    • Start the variable name with a lowercase letter.
    • Use camel case for multi-word variable names (e.g., myNumber).
    • Avoid using reserved keywords as variable names (e., int, class, etc.).
    • Choose descriptive names to indicate the purpose of the variable.


    In this tutorial, we learned about declaring and initializing integer variables in Java. We explored various ways to declare and initialize integers, including type inference, multiple variables declaration, and widening conversion using floating-point literals. Additionally, we discussed the importance of following naming conventions for variables to write clean and readable code.

    The proper declaration of integer variables is crucial in Java programming as it sets the foundation for performing mathematical calculations, counting elements, and much more. By understanding these concepts and applying them in your programs, you’ll be able to work effectively with integers in Java.

    We hope this tutorial has provided you with a clear understanding of how to declare an integer data type in Java!

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