The Primitive Types
Java defines eight primitive types of data: byte, short, int, long, char, float, double, and boolean.
| Primitive Type | Reserved Word | Size | Min Value | Max Value |
|---|---|---|---|---|
| Boolean | boolean | N/A | N/A | N/A |
| Character | char | 16-bit | Unicode 0 | Unicode 216 - 1 |
| Byte integer | byte | 8-bit | -128 | +127 |
| Short integer | short | 16-bit | -21 | +215 - 1 |
| Integer | int | 32-bit | -231 | +231 - 1 |
| Long integer | long | 64-bit | -263 | +263 - 1 |
| Floating-point | float | 32-bit | 1.4e-045 | 3.4e+038 |
| Double precision floating-point | double | 64-bit | 4.9e-324 | 1.8e+308 |
byte, short, int, and long are for whole-valued signed numbers. float and double are fractional precision numbers.
char represents symbols in a character set, like letters and numbers. boolean represents true/false values.
Integers
Java defines four integer types: byte, short, int, and long.
Integer types are signed, positive and negative values.
The width and ranges of these integer types vary widely:
| Name | Width | Range |
|---|---|---|
| long | 64 | -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
| int | 32 | -2,147,483,648 to 2,147,483,647 |
| short | 16 | -32,768 to 32,767 |
| byte | 8 | -128 to 127 |
Floating Point Types
There are two kinds of floating-point types: float and double. float type represents single-precision numbers. double type stores double-precision numbers.
Floating-Point Types width and ranges are shown here:
| Name | Width in Bits | Approximate Range |
|---|---|---|
| double | 64 | 4.9e-324 to 1.8e+308 |
| float | 32 | 1.4e-045 to 3.4e+038 |