Data types
There are two types of data types.
- Primitive Data Types
- User Defined Data Types
Primitive Data Types
info
There are 8 primitive data types available in Java. 8 keywords are defined to represent 8 primitive data types.
Following are primitive data types:
- boolean
- byte
- char
- short
- int
- long
- float
- double
User-Defined Data Types
There are four types of user defined data types.
- Class Types
- Interface Types
- Enum Types(from Java5)
- Annotation Types(From Java5)
Java Data Types
This table outlines all primitive and user-defined data types in Java, including their size, default values, and min/max ranges.
| Type | Size (bits) | Size (bytes) | Default Value | Min Value | Max Value |
|---|---|---|---|---|---|
boolean | 1 (logical only) | JVM dependent | false | false | true |
byte | 8 | 1 | 0 | -128 | 127 |
char | 16 | 2 | \u0000 | \u0000 (0) | \uffff (65,535) |
short | 16 | 2 | 0 | -32,768 | 32,767 |
int | 32 | 4 | 0 | -2,147,483,648 | 2,147,483,647 |
long | 64 | 8 | 0L | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 |
float | 32 | 4 | 0.0f | ~1.4e-45 (positive) | ~3.4028235e+38 |
double | 64 | 8 | 0.0d | ~4.9e-324 (positive) | ~1.7976931348623157e+308 |
| User-defined (class, interface, enum, record) | ~64 (JVM dependent) | ~8 (or 4) | null | N/A | N/A |
📝 Note: User-defined types are reference types. The actual object may use more memory, but the reference itself is typically 4 or 8 bytes, depending on JVM architecture and settings (like Compressed OOPs).