Java Data Types

Used for storing whole numbers without decimals.

byte 8-bit. Used to save space in large arrays. Range: -128 to 127.

short 16-bit. 2x smaller than int. Range: -32,768 to 32,767.

int 32-bit. The default choice for whole numbers.

long 64-bit. Used when int is not large enough. Ends with 'L' (e.g., 100L).

Used for numbers with fractional parts (decimals).

float 32-bit (Single precision). Ends with 'f'. Not for precise currency. float f1 = 234.5f;

double 64-bit (Double precision). The default choice for decimals. double d1 = 123.4;

boolean

Represents one bit of information (True/False). Used for flags and conditional logic.

boolean isActive = true;

char

16-bit Unicode character. Stores a single character.

char letter = 'A';

Reference variables are created using class constructors. They store the address of the object, not the value itself.

Type	Size (Bits)	Default Value	Range / Description
byte	8	0	-128 to 127
short	16	0	-32,768 to 32,767
int	32	0	-2³¹ to 2³¹-1
long	64	0L	-2⁶³ to 2⁶³-1
float	32	0.0f	7 decimal digits of precision
double	64	0.0d	15 decimal digits of precision
char	16	'\u0000'	0 to 65,535 (Unicode)
boolean	1*	false	true / false
String	N/A	null	Sequence of characters

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