Java-2018-1-9 first,

Java-2018-1-9 first,

Today is the first day of the final exam, and the first day of getting started with Java. If you don't want to review it, learn something new !!

Three major Java platforms

1. Java SE

There are four parts: JVM (Virtual Machine), JRE (runtime environment), JDK (Development Kit), Java

2. Java EE

3. Java ME --- (used less)

Java Development Environment Configuration

Notepad/ediplus/ultreadit

Eclipse/MyEclipse

JCreator

Betbeans

IntelliJ IDEA

Java commands

Note: in Java, the first letter of the class and constant name is capitalized, and the class name is consistent with the file name.

Java Command Execution

Javac compilation command: Java compilation, generate. class bytecode File

Note: 1. Document Note:/***/, two. usually add the copyright statement 2. Multi-line comment:/**/One * 3. Single-line comment ://

First Attempt: (Note: // String, the first letter of the System must be capitalized) // String [] args or string args [] print ("\ n") is equivalent to println ("")

Public class Myfirst {
Public static void main (String [] args ){
System. out. println ("my first java !! ");
}
}