What are Data Types in Java?

Data types define the type of value a variable can store. Every variable in Java must have a data type.

Data types help Java allocate memory efficiently and perform operations correctly.

Types of Data Types

Java data types are divided into two categories:

Primitive Data Types
Non-Primitive Data Types

Primitive Data Types

Primitive data types are predefined by Java and store simple values.

Data Type	Size	Description	Example
byte	1 byte	Small integer	100
short	2 bytes	Short integer	5000
int	4 bytes	Integer numbers	100000
long	8 bytes	Large integers	99999999L
float	4 bytes	Decimal numbers	10.5f
double	8 bytes	Large decimal numbers	99.99
char	2 bytes	Single character	'A'
boolean	1 bit	true or false	true

byte Data Type

byte is used to store small integer values.

byte age = 25;

System.out.println(age);

Range of byte is from -128 to 127.

short Data Type

short stores larger values than byte.

short number = 15000;

int Data Type

int is the most commonly used integer data type in Java.

int marks = 95;

long Data Type

long is used for very large integer values.

long population = 999999999L;

float Data Type

float stores decimal numbers with less precision.

float price = 10.5f;

double Data Type

double stores decimal numbers with high precision.

double salary = 45678.99;

char Data Type

char stores a single character.

char grade = 'A';

boolean Data Type

boolean stores only true or false values.

boolean isJavaEasy = true;

Non-Primitive Data Types

Non-primitive data types are created by programmers and store complex data.

String
Arrays
Classes
Interfaces
Objects

String Data Type

String stores text values.

String name = "CodeVyro";

Primitive vs Non-Primitive Data Types

Primitive	Non-Primitive
Predefined by Java	Created by programmer
Stores simple values	Stores objects and references
Fixed memory size	Memory size may vary
Faster performance	Slightly slower

Default Values of Primitive Data Types

Data Type	Default Value
byte	0
short	0
int	0
long	0L
float	0.0f
double	0.0d
char	'\u0000'
boolean	false

Complete Java Data Types Example

public class Main {

    public static void main(String[] args) {

        int age = 25;

        double salary = 55000.50;

        char grade = 'A';

        boolean passed = true;

        String name = "Alex";

        System.out.println(age);

        System.out.println(salary);

        System.out.println(grade);

        System.out.println(passed);

        System.out.println(name);

    }

}

Output

25
55000.5
A
true
Alex

Best Practices

Use int for normal integer values
Use double for decimal numbers
Use boolean for conditions
Use meaningful variable names
Choose correct data type to save memory

Common Errors

Assigning wrong value to variable
Using incorrect suffix for float or long
Storing large values in small data type
Using double quotes instead of single quotes for char

Conclusion

Java data types are essential for storing and managing data efficiently. Understanding data types properly helps developers write optimized, clean, and error free programs.