Java Data Types

In order to store different types of data, Java has different data type specifiers. To store integer numbers, there are data types such as byte, short, int and long depending on how large or small value to be stored.

byte data type

byte can only store values between -128 and 127. byte occupies only 1 byte in memory.
Other number data types are explained in the table below.

float data type

float and double are data types to store floating point numbers based on how large or small value to be stored.

char data type

char data type is used to store single character such as alphabets in upper case or lower case, digits or special characters. char data type is used to store unicode characters. char data type occupies 2 bytes.

boolean data type

boolean data type is used to store only one of two values - true or false. boolean values are not used to store the words true or false but the result of a condition like "is a equal to b?" or "is a>b ?" or any other condition. There is only one of the two possible results for a condition such as either true or false.

Size in memory and values that can be represented in all the Java data types are shown below.

Java Data type	Size	Minimum Value	Maximum Value
byte	1 byte	-2⁷ equal to -128	2⁷-1 equal to 127
short	2 bytes	-2¹⁵ equal to -32768	2¹⁵-1 equal to 32767
int	4 bytes	-2³¹ equal to -2147483648	2³¹-1 equal to 2147483647
long	8 bytes	-2⁶³ equal to -9223372036854775808	2⁶³-1 equal to 9223372036854775807
float	4 bytes	Minimum Negative: -4286578688, Smallest positive: 1.401298464324817070 9237295832899e-45	Largest positive: 2139095040
double	8 bytes	Minimum Negative: -4503599627370496, Smallest positive: 4.940656458412465441 7656879286822e-324	Largest positive: 1.797693134862315708145274237317e+308
char	2 bytes	UTF-16 reprsentation. \u0000 to \uFFFF, \uD800 to \uDBFF, \uDC00 to \uDFFF
boolean		true, false

Java Data type	Size
byte	1 byte
short	2 bytes
int	4 bytes
long	8 bytes
float	4 bytes
double	8 bytes
char	2 bytes
boolean

Java Data type	Minimum Value
byte	-2⁷ equal to -128
short	-2¹⁵ equal to -32768
int	-2³¹ equal to -2147483648
long	-2⁶³ equal to -9223372036854775808
float	Minimum Negative: -4286578688, Smallest positive: 1.401298464324817070 9237295832899e-45
double	Minimum Negative: -4503599627370496, Smallest positive: 4.9406564584124654417 656879286822e-324
char	UTF-16 reprsentation. \u0000 to \uFFFF, \uD800 to \uDBFF, \uDC00 to \uDFFF
boolean	true, false

Java Data type	Maximum Value
byte	2⁷-1 equal to 127
short	2¹⁵-1 equal to 32767
int	2³¹-1 equal to 2147483647
long	2⁶³-1 equal to 9223372036854775807
float	Largest positive: 2139095040
double	Largest positive: 1.797693134862315708 145274237317e+308

Literals

Integer Literals

Integer literals can be decimal literals, binary literals, octal literals or hexadecimal literals.

Decimal literals

Decimal literals correspond to decimal numbers in the number system. Decimal numbers are numbers in the regular usage. Decimal numbers are in base 10 and use the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9
Examples:

2
4
65000

Binary literals

Binary literals correspond to Binary numbers in the number system. Binary numbers are in base 2 and use the digits 0 and 1 only.
Binary Literals are represented in Java with leading 0b
Examples

0b101011101
0b1110
0b101110
0b1101

Octal literals

Octal literals correspond to Octal numbers in the number system. Octal numbers are in base 8 and use the digits 0, 1, 2, 3, 4, 5, 6 and 7 only.
Octal Literals are represented in Java with leading 0
Examples

0234
045
09000

HexaDecimal literals

HexaDecimal literals correspond to HexaDecimal numbers in the number system. Decimal numbers are numbers in base 16 and use the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F
Hexadecimal Literals are represented in Java with leading 0x

0x456
0x5006
0x56000

long Literals

long Literals are represented in Java with numbers ending with L or l (uppercase or lowercase). However, it is better to represent using the uppercase L since lowercase appears similar to the number 1 and it could be confusing. long numbers are used when the numerals used in expressions return results, that are larger than what could be held in an int.

2242003040L
3400000000L
4500000000L
5600000000L
6566600000330L
5678L

float Literals

float Literals are represented in Java with numbers ending with F or f (uppercase or lowercase)

45.67f
105.678923f
0.7f
56.7e6f

double Literals

double Literals are represented in Java with numbers ending with D or d (uppercase or lowercase)


45.67
100.678
0.7
45.6e12
56.7e6

char Literals

char literals are literals that represent only one character. char literals are represented within single quotes. Since it is unicode, it can be used to represent any characters in various language character sets across the world. Unicode characters that are not available in keyboard are represented in Java using the escape \u followed by 4 hexadecimal digits. Examples are shown below.

'c'
'M'
'\u0B85' to represent அ
'\u0A20' to represent ਠ
'\u03B1' to represent α
'\u0232' to represent Ȳ
'\u0041' to represent A
'\u0031' to represent 1

Java also supports the following char literals to represent escape characters

\b (backspace), \t (tab)
\n (line feed), \f (form feed)
\r (carriage return)
\" (double quote), \' (single quote)
\\ (backslash)

String Literals

String literals can be stored in an instance of String. String data type is used to store characters, words, sentences and any amount of text content. While all other literals are stored in primitve data type, String literals are stored as objects.

"Good"
"Morning"
"There is a way"
"How are you? Nice to meet you. 'I am good'"

boolean literals

true
false

Underscores in Numeric characters

Underscores can be used in numbers between digits similar to using commas while writing numbers.

Underscores can be used in the following places

between digits or hexadecimal characters in Integers
between digits or hexadecimal characters on either side of the decimal point in floating point numbers.

Underscores can not be used in the following places

immediately before or after the decimal point in floating point numbers
at the start or end of the numbers
immediately before or after L or l used in long literals
immediately before or after F or f used at the end of float literals
immediately before or after D or d used at the end of double literals
immediately before, after, or in middle of 0x used in hexadecimal literals
immediately before, after, or in middle of 0b used in binary literals
immediately before or after 0 used in Octal literals

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Java Data types