Chapter One Introduction to Java

1. Installation and configuration of JDK

(1) Install the JDK directly (Java SDK with JRE included)

(2) Configuring environment variables: My Computer--right-click Property--Advanced--environment variable--system environment variable--path--edit (Configure the installation path of the JDK to the path attribute)

(3) Start command line mode: After the configuration is successful, enter "CMD" in the Run interface and enter Javac

2, the first program

1  Public class haha{2      Public Static void Main (String args[]) {3         SYSTEM.OUT.PRINTLN ("I Java"); 4     }5 }

Javac compiler: Compile the. java file into a. class file (a class file is one)

Java Runtime class file: specific as follows

Note: Common errors are as follows:

• Main () is written in Mian ()
• String is written in sting
• The file name is the class name of the public class--〉 first capitalization, hump principle

Chapter One Introduction to Java