Primitive Data Types

What are data types in java?

In Java, data types specify the type of data that a variable can hold. Java is a strongly-typed language, meaning that each variable must be declared with a specific data type. This helps in ensuring that operations on the data are performed correctly. Java has two main categories of data types:

1. Primitive Data Types
2. Reference/Object Data Type

1. Primitive Data Types #

Primitive data types are the most basic data types built into the language. There are eight primitive data types in Java:

1. byte

• Size: 1 byte (8 bits)
• Range: -128 to 127
• Usage: Useful for saving memory in large arrays where the memory savings matter.

Example:

byte b = 100;

System.out.println("Byte value: " + b);  // Output: Byte value: 100

2. short

• Size: 2 bytes (16 bits)
• Range: -32,768 to 32,767
• Usage: Can be used to save memory in large arrays when the range of values is known to be limited.

Example:

short s = 1000;

System.out.println("Short value: " + s);  // Output: Short value: 1000

3. int

• Size: 4 bytes (32 bits)
• Range: -2^31 to 2^31-1
• Usage: Default data type for integral values unless there is a concern about memory.

Example:

int i = 100000;

System.out.println("Int value: " + i);  // Output: Int value: 100000

4. long

• Size: 8 bytes (64 bits)
• Range: -2^63 to 2^63-1
• Usage: Used when a wider range than int is needed.

Example:

long l = 100000L;

System.out.println("Long value: " + l);  // Output: Long value: 100000

5. float

• Size: 4 bytes (32 bits)
• Range: Approximately ±3.40282347E+38F (6-7 significant decimal digits)
• Usage: Used when fractional precision is needed. Suffix f or F is mandatory.

Example:

float f = 10.5f;

System.out.println("Float value: " + f);  // Output: Float value: 10.5

6. double

• Size: 8 bytes (64 bits)
• Range: Approximately ±1.79769313486231570E+308 (15 significant decimal digits)
• Usage: Default data type for decimal values. Use double for precise calculations.

Example:

double d = 10.5;

System.out.println("Double value: " + d);  // Output: Double value: 10.5

7. boolean

• Size: 1 bit (Java uses 1 byte internally)
• Values: true or false
• Usage: Used for simple flags that track true/false conditions.

Example:

boolean flag = true;

System.out.println("Boolean value: " + flag);  // Output: Boolean value: true

8. char

• Size: 2 bytes (16 bits)
• Range: 0 to 65,535 (unsigned)
• Usage: Used to store any character.

Example:

char c = 'A';

System.out.println("Char value: " + c);  // Output: Char value: A

Summary #

Here is a consolidated example that uses all the primitive data types:

public class Main {

    public static void main(String[] args) {

        // byte example

        byte b = 100;

        System.out.println("Byte value: " + b);  

        // short example

        short s = 1000;

        System.out.println("Short value: " + s); 

        // int example

        int i = 100000;

        System.out.println("Int value: " + i); 

        // long example

        long l = 100000L;

        System.out.println("Long value: " + l);  

        // float example

        float f = 10.5f;

        System.out.println("Float value: " + f); 

        // double example

        double d = 10.5;

        System.out.println("Double value: " + d);  

        // boolean example

        boolean flag = true;

        System.out.println("Boolean value: " + flag);  

        // char example

        char c = 'A';

        System.out.println("Char value: " + c); 

    }

}

Output:

Byte value: 100
Short value: 1000
Int value: 100000
Long value: 100000
Float value: 10.5
Double value: 10.5
Boolean value: true
Char value: A