First, java is like this
1. Origin: JAVA was developed by Sun Corporation .
2. Extension: The extension of JAVA source code is .java
JAVA class file extension is .class
3. Application Technology Platform: Java SE and Java EE
2. Tips, it's all up to him to type the code
1. sysout+"Alt+/" to get System.out.println("");
2. ctrl+spacebar to switch the input method to English in one step
3. F5 refresh
4.ctrl+A select all
5.ctrl+I brace alignment
6.ctrl+D delete the current line
For more, please see the blog in the future, I am learning. . .
3. Words, my peers
A tools and understanding
JDK (Java Development Kit) java development kit
JVM (Java Virtual Machine) java virtual machine
Javac compile command
java interprets the run command
Javadoc Generate java documentation command
classpath classpath
Version
author author
public public
class class
static
void has no return value
String String class
System system class
out output
print peer print
println print newline
JIT (just-in-time) processing in time
B data type
byte byte
char character
boolean boolean
short short integer
int shaping
long long shape
float floating point type
double double precision
if if
else else
switch demultiplexing
case matches constant value
break to terminate
default default
while when the loop
do until loop
for loop with known number of times
continue to end this loop and proceed to the next descending generation
length gets the number of elements in the array
D about the class
OOP object oriented programming
Object object
Class class
Class member
Class method
Class variable Class variable
Constructor Constructor
Package Package
Import package import package
For more, please see the blog in the future, I am learning. . .
Fourth, follow the code, get started
public class Cat{ //Cat: This position is the class name, the first letter needs to be capitalized public: modifier
public static void main (String[] args){ // main: java program execution entry.
system.out.println("We are cats"); //The java output statement must end with a semicolon.
//println: output and wrap print: direct output without wrapping
//"We are cats", write the statement to be output in both Chinese and English (string)
}
}
// { } must be English characters
// A line of comment is // the content of the comment
Multi-line comments are /*
*Note content
*Note content
*/
//.........\n....... The escape character \n is a newline approximately equal to println