Java course

Java By Sun Microsystems The company was founded on 1995 year 5 High level programming language launched in June .

Java Can run on multiple platforms , as Windows, Mac OS And many other UNIX Version of the system .

This tutorial will give you a better understanding of Java programing language .

Mobile operating system Android Most of the code uses Java Programming language programming .

Java Online tools

JDK 11 Online Chinese Manual


My first JAVA Program

Let's use a simple example to show Java Programming , Create file HelloWorld.java( The file name must be consistent with the class name ), The code is as follows :

example

public class HelloWorld { public static void main ( String [ ] args ) { System . out . println ( " Hello World " ) ; } }

Run instance »

notes :String args[] And String[] args Can execute , But... Is recommended String[] args, This can avoid ambiguity and Misreading .

Run the above example , The output results are as follows :

$ javac HelloWorld.java
$ java HelloWorld
Hello World

Execute command parsing :

We used two commands above javac and java.

javac Followed by java File name of the file , For example HelloWorld.java. This command is used to convert java The source file is compiled as class Bytecode file , as : javac HelloWorld.java.

function javac After the command , If the compilation is successful and there are no errors , There will be a HelloWorld.class My files .

java Followed by java Class name in file , For example HelloWorld Is the class name , as : java HelloWorld.

be careful :java Don't add... After the command .class.

Gif Figure shows :


Start learning JAVA Programming