Primitive types

There are eight primitive types in Java. These are the fundamental "atoms" from which all other types are constructed.

Type	What it means	Example literals	Range	Comments
byte	An eight-bit integer	-5, 0, 5	-128 to 127	Seldom used
short	A two-byte integer	-5, 0, 5, 200	-32768 to 32767	Seldom used
int	A four-byte integer	-5, 0, 5, 200, 50000	Negative to positive two billion	Typically used for integers
long	An eight-byte integer	-5L, 0L, 5L, 999999999999L	-9 * 1018 to 9*1018	Used only when very large integers are needed
char	A single character (usually two bytes)	'a', 'A', '5', '+', ' ', '\n', '\'', '\\'	Most of the world's characters, including Chinese, Arabic, etc.	Can be treated as integers; some characters cannot be typed as single characters
float	A four-byte decimal number	5.23F, -123.45678F	1.4*10-45 to 3.4*1038	Seldom used
double	An eight-byte decimal number	5.23, -123.45678	4.9*10-324 to 1.8*10308	Typically used for decimal ("floating point") numbers
boolean	A logical value (one byte long)	true, false	Only the two values true and false	Used mostly for remembering the results of tests

In addition, Java defines literally thousands of object types (which you can explore at http://java.sun.com/j2se/1.5.0/docs/api/index.html), and every program you write has additional programmer-defined object types of its own.

Any primitive type (except boolean) can be cast to any other primitive type (except boolean).