Java tutorial

Literals

Literal is a value of any type given explicitly. So in expression x+10, x is variable and 10 numeric literal.
Sign + or - can be consider as part of the numeric literal or as expression with unary + and -.

example	description
23 +23 -23 20L	Decimal integer literal is defined as sequence of digits without a leading 0 (zero). Integer types represents by byte - value must be in range [-128; 127] short - value must be in range [-32,768; 32,767] int - value must be in the range [-2³¹; 2³¹-1]. This is default type. long - value must be in the range [-2³¹; 2³¹-1] and must have suffix L or l. L is preferred because it is easier to distinguish from 1. Since Java SE 8 you can use unsigned integers.
023 0o23 -023	An octal integer literal is defined as sequence of 0-7 digits with leading 0 or prefix 0o.
0x23 0x23AAbb -0xabcde	A hexadecimal integer literal is defined as sequence of 0-9 digits and letters a-f or A-F with prefix 0x or 0X. Case of letters is meaningless, so 0xa = 0xA = 10 and 0xf = 0xF = 15
0b11 -0b0001	A binary integer literal is defined as sequence of 0 and 1 with prefix 0b or 0B.
1.234e2 -.1415926 123.4f 123.4d	There are two types for represent floating-point numbers: double and float. A floating-point literal is of type float if it ends with the letter F or f; otherwise its type is double and it can optionally end with the letter D or d. Java supports a scientific notation, i.e. literals can use E or e.
true false	true and false are boolean literals.
{1,2,3} { "a", "c", strvar}	A array literal is defined as sequence of values in curly braces.
'A'	A character literal is a character in single quotes. May contain any Unicode (UTF-16) character. If your editor and file system allow it, you can use such characters directly in your code. If not, you can use a "Unicode escape": \uxxxx.
"str\u00F1" "line1\n\rline2"	A string literal is a sequence of characters in double quotes. May contain any Unicode (UTF-16) characters. If your editor and file system allow it, you can use such characters directly in your code. If not, you can use a "Unicode escape": \uxxxx.

underscore in numerical literals

Any number of underscore _ characters can appear anywhere between digits in a numerical literal.

long creditCardNumber = 1234_5678_9012_3456L;
int hexBytes = 0xFF_EC_DE_5E;
float pi =  3.14_15F;

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