Tipos de dados primitivos
byte: 8-bit signed. -128 a 127 (inclusive).
short: 16-bit signed. -32,768 a 32,767 (inclusive).
int: 32-bit signed. -2,147,483,648 a 2,147,483,647 (inclusive).
long: 64-bit signed. -9,223,372,036,854,775,808 a 9,223,372,036,854,775,807 (inclusive).
float: single-precision 32-bit IEEE 754 floating point.
double: double-precision 64-bit IEEE 754 floating point.
boolean: represents one bit of information, but its "size" isn't something that's precisely defined.
char: single 16-bit Unicode character
Fonte: http://download.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html