Comment:
1: Multi-line / * * /
2: single //
3: Documentation / ** * /
Basic data types:
1: Shaping byte (1)
Short (2) int (. 4)
long (. 8) (generally stated to be of type long time after the number assignment plus L)
2: float
float
(when float to the assignment of the back to add f)
Double
3: Character
char (2) (
a character in a computer do not exist, are aligned in fact converted from ASCLL A 65 a 97 b 98 a numerical relationships)
4: boolean
boolean (to true
false)
Data type conversion
1: Automatic data type conversion (small data type to large data type)
2: mandatory data type conversion (conversion between floating point and plastic note when converted lose precision)
variable
1: variable assignment (data type variable name = value)
2: Identifier (1: 2 can not keyword conflicts: can appear only alphanumeric, can appear only alphanumeric, $, and underscore _ and the first character can not be a number 3. Italy 4. hump see the name to know the rules and variable names method name: the first letter lowercase, if more than one word, the word capitalized other class name: the first letter capitalized, if there is more than one word, the other word capitalized)
3:
identifier case sensitive (int a = 19; int A = 20; a and A are not the same)
Operators
1: arithmetic operators (+ - * / modulus (remainder) operator
%
）
2: assignment operator (= the value assigned to the right of left)
3: relational operators
( // relational operators> <> = <= = ==!
The end result // relational operators are Boolean values
）
4: logical operators (also known as short-circuiting operator && || ultimately returns a Boolean value)