Java DataType

Every Variable in Java has a data type. Data types specify the size and types of values that can be stored.

In Java, a data type defines the type of data that a variable can hold. It determines the size and type of values that can be stored in memory.

Java provides a variety of data types, which can be broadly categorized into primitive and non-primitive data types.

Primitive Data Types

Java defines eight primitive types of data: byte, short, int, long, float, double, char, and boolean.

Integer Types

Java supports four types of Integer.

1. byte

Width: 1 byte

Range: Stores small integer values from -128 to 127.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        byte smallNumber = 110;
        System.out.println("Byte Value: " + smallNumber);
    }
}

2. short

Width: 2 byte

Range: Stores medium-range integer values from -32,768 to 32,767.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        short mediumNumber = 32000;
        System.out.println("Short Value: " + mediumNumber);
    }
}

3. int

Width: 4 byte

Range: Stores large integer values from -2,147,483,648 to 2,147,483,647.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        int largeNumber = 1000000;
        System.out.println("Int Value: " + largeNumber);
    }
}

4. long

Width: 6 byte

Range: Stores very large integer values. Must be suffixed with L (e.g., 10000000000L).

Example

public class DataTypeExample {
    public static void main(String[] args) {
        long veryLargeNumber = 10000000000L;
        System.out.println("Long Value: " + veryLargeNumber);
    }
}

Floating-Point Types

This group includes float and double, which represent numbers with fractional precision.

1. float

Width: 4 byte

Range: Used for decimal numbers with single precision. Must be suffixed with f (e.g., 10.5f).

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        float decimalValue = 5.75f;
        System.out.println("Float Value: " + decimalValue);
    }
}

2. double

Width: 8 byte

Range: Used for decimal numbers with double precision (default for floating-point literals).

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        double largeDecimalValue = 20.99;
        System.out.println("Double Value: " + largeDecimalValue);
    }
}

Character Type

1. char: Stores a single 16-bit Unicode character.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        char letter = 'A';
        System.out.println("Character Value: " + letter);
    }
}

Boolean Type

1. boolean: Stores only true or false.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        boolean isJavaFun = true;
        System.out.println("Boolean Value: " + isJavaFun);
    }
}

2. Non-Primitive Data Types

a. String: Stores a sequence of characters.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        String message = "Hello, Java!";
        System.out.println("String Value: " + message);
    }
}

b. Array: Stores a collection of values of the same type.

Example:

public class DataTypeExample {
    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40};
        System.out.println("Array Value at Index 2: " + numbers[2]);
    }
}

Java DataType – Interview Questions

Java Data Type – Objective Questions (MCQs)

Related Java Data Type Topics