Section one (first Java program)

//Compile HelloWorld program  Public class HelloWorld {

/*
Public represents the meaning of the global
Static represents a statically
Void has no return value
Main is the entry method in Java, and the name of this main cannot be changed.
Args is a parameter name that you can define arbitrarily
*/

 Public Static void Main (string[] args) {        System. out. println ("HelloWorld");}    }

//use the public class to declare class, then the file name must be exactly the same as the class name (including case)//class is used to declare classes, and filenames can be any valid file name,//the file name does not need to match the class class but the generated class file name matches the class name.//does not and the original file name one//javac Path (file path at end of. Java)//Java class name Public classming{ Public Static voidMain (string[] args) {System. out. println ("Ming is very handsome! "); }}classa{ Public Static voidMain (string[] args) {System. out. println ("Ming is the most handsome! "); }}classk{ Public Static voidMain (string[] args) {System. out. println ("Ming is still very handsome! "); }}classm{ Public Static voidMain (string[] args) {System. out. println ("Ming is the most beautiful! "); }}

Static void Main (String args[]) method starts execution

//for all classes, the first letter of the class name should be capitalized. If the class name consists of several words,//so the first letter of each word should be capitalized, such as HelloWorld? Public classtest{//All method names should start with a lowercase letter. If the method name contains several words,//The first letter of each of the following words is capitalized. Getemailbyid ()     PublicString Getemailbyid (intID) {                return NULL; }         Public Static voidMain (string[] args) {}}

Section one (first Java program)