First Java Code - Run a demo pro

Coding Java

the java filename should be the same as the name behind class statement, extention should be .java.

class FirstJava {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

ComplieTool:

1. javac.exe
   complie java file, generate .class file

C:\Users\Janus_admin\Documents\Oth\java>javac FirstJava.java

2. java.exe
   execute the .class file, return the result.
   Attention: this step please don't add the extention

C:\Users\Janus_admin\Documents\Oth\java>java FirstJava
Hello, world!