Java has eight primitive data types: byte, short, int, long, float, double, char, and boolean. These types represent raw values (not objects) and are stored directly in memory, each with a specific size and value range.

• byte: 8-bit signed integer, range -128 to 127; used for memory-efficient arrays;
• short: 16-bit signed integer, range -32,768 to 32,767; used in memory-constrained environments;
• int: 32-bit signed integer, range -2,147,483,648 to 2,147,483,647; default for integers;
• long: 64-bit signed integer, range -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807; for large integers;
• float: 32-bit floating-point, approximate range ~1.4E-45 to ~3.4E+38; memory-efficient decimals;
• double: 64-bit floating-point, approximate range ~4.9E-324 to ~1.8E+308; default for decimals;
• char: 16-bit Unicode character, range '\u0000' to '\uffff'; stores characters;
• boolean: represents true or false; used for logical values.

Default values: numeric types default to zero, char to '\u0000', and boolean to false.

To help you compare these types, here is a table summarizing their key properties:

Type	Size (bits)	Value Range	Default Value	Typical Use Case
byte	8	-128 to 127	0	Memory-efficient integer arrays
short	16	-32,768 to 32,767	0	Legacy code, memory-constrained env.;
int	32	-2,147,483,648 to 2,147,483,647	0	General-purpose integer values
long	64	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	0	Large integer values
float	32	~1.4E-45 to ~3.4E+38 (approximate)	0.0f	Memory-efficient decimal numbers
double	64	~4.9E-324 to ~1.8E+308 (approximate)	0.0d	Default for decimal numbers
char	16	'\u0000' (0) to '\uffff' (65,535)	'\u0000'	Storing characters
boolean	1 (virtual)	true or false	false	Logical values

Note: The boolean type does not have a precisely defined size in memory; its size is determined by the Java Virtual Machine implementation.