Java Data Types (Numbers)

In Java, data types define what kind of value a variable can store and how much memory it uses.

 

Java data types are mainly divided into:

 

Primitive Data Types

 

• Non-Primitive (Reference) Data Types
• Number Types (Primitive)

 

Number types store numeric values. They are divided into:

 

• Integer Types (Whole Numbers)

 

Type	Size	Example	Range
byte	1 byte	100	-128 to 127
short	2 bytes	5000	-32,768 to 32,767
int	4 bytes	100000	-2,147,483,648 to 2,147,483,647
long	8 bytes	10000000000L	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

 

Example:

int age = 25;

long population = 8000000000L;

👉 Use int for most whole numbers.

👉 Use long for very large numbers.

 

B. Floating-Point Types (Decimal Numbers)

 

Type	Size	Example	Range
float	4 bytes	3.14f	±1.4E-45 to ±3.4E+38.
double	8 bytes	3.14159	-1.7976931348623157E+308 to 1.7976931348623157E+308

 

Example:

float price = 19.99f;

double pi = 3.1415926535;

👉 double is more precise than float.

👉 Decimal numbers default to double.