Java Learning (1) Environment setup, hello world demo, hellodemo

Java Learning (1) Environment setup, hello world demo, hellodemo

This program is a front-end developer who occasionally has spare time at work. He may wish to study it. Otherwise, how can he keep his face blank and embark on the peak of his life?

To be honest, every language is connected. With the foundation of javascript and two or three years of experience in dealing with java, it is not very difficult to simply learn java. Okay, you don't have to talk about it. Let's get started!

 

Environment Configuration

First of all, I am a little white. I don't know anything about java.

Jdk

Software Development Kit

Core of java Development

Including the java Runtime Environment, java tools, and java-based Class Libraries

Jre

Runtime Environment, jvm standard implementation and core class library

 

JDK = JRE + development tool set (for example, javac compilation tool)
JRE = JVM + java SE standard class library

(What I see on the Internet seems to be the essence !)

　　

Eclipse

Anyway, my friend suggested using myeclipse. I just used it if I didn't make it.

Environment Variable

I will provide a reference connection for this configuration.

Http://www.cnblogs.com/Belieflee/p/4778315.html

 

For now, I know that I want to prepare so many items. I will try again later.

Hello world: what is the beginning of each language?

　　

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

　　

Command javac: Compile. java into. class

Command java: execute a class (the class name in the java + java file)

 

Use eclipse to run java programs

Open myeclipse

File-> New-> Java Project-> Finish

Open the project and select src

Right-click and choose New> Class.

　　

Run: select the java file-> right-click-> Run as-> 1 Java Application

It is about to write a helloworld and then run the following

　　

Reference: http://www.runoob.com/java/java-environment-setup.html

The video above provides a good explanation.