Primitive data types

Java has eight primitive data types that represent simple values. They are not objects and are stored directly in memory.

Type	Size	Range / Values
`byte`	1 byte	-128 to 127
`short`	2 bytes	-32,768 to 32,767
`int`	4 bytes	-2³¹ to 2³¹‑1 (≈ ±2.1 billion)
`long`	8 bytes	-2⁶³ to 2⁶³‑1
`float`	4 bytes	±3.4E‑38 to ±3.4E+38 (6‑7 significant digits)
`double`	8 bytes	±1.7E‑308 to ±1.7E+308 (15 significant digits)
`char`	2 bytes	0 to 65,535 (Unicode characters)
`boolean`	not precisely defined	`true` or `false`

Why primitives?

Performance: faster than objects because they live on the stack.
Simplicity: directly represent numbers, characters, and booleans.

Examples:

byte b = 100;
short s = 30000;
int i = 2_000_000;      // underscores for readability
long l = 9_000_000_000L; // L suffix for long
float f = 3.14f;         // f suffix for float
double d = 3.1415926535;
char c = 'A';
boolean flag = false;