Java Basic Learning Path (i)

Java Basic Concepts:

Pathl:path is a property of the operating system and is the path that the system uses to search for executable files, and the personal understanding is similar to the global variables in Linux

Calsspath:java the path of the file to be loaded when the program interprets the class file

Comments:

Single-line comment//

Multi-line Comment/*.......*/

Document Comment/**......*/

Java two kinds of data types:

1 Basic types

Numeric type:

Shaping: Short, Int,long

Floating point type: float,double

Character type: Char

Boolean Type: Boolean

2 reference types

arrays, classes, interfaces

Basic principles of data type conversion:

• Automatic conversion to a wide range when calculating small and large range numbers
• Note overflow when converting to a large range, must use CAST (number plus l, or number of previous plus (data type))

Operator:

• Trinocular operator:a>b?command1:command2;
• Differences with & and &&:& will judge two conditions, even if the first one is not satisfied, will still judge the second one, and && will only judge the first, if not satisfied will exit
• | and | | The difference: ditto
• ！ Non -

Java Basic Learning Path (i)