Java SE Basics section

Introduction to the Java language:

Javase: Basic Edition, Basic language, laying the groundwork for post-development work
Javame: Small version, mainly for small business payment platform
Java EE: Enterprise Edition, Web orientation

J2SE, J2ME, Java

after jdk1.5, renamed to Javase

First, install the JDK, build the development environment

1. Concept:

JVM: (Java Virtual machine)-java virtual machines, all Java programs need to be run in a Java Virtual machine

JRE: (Java Runtime Environment)-java runtime Environment, contains JVM, and contains core class libraries required for Java programs to run

JDK: (Java Development Kit)-java SDK, contains the JRE, and includes the tools needed for Java development

So when it comes to setting up the environment, it's just enough to install the JDK.

2. Install JDK, download URL: www.oracle.com

3. Configure Environment variables:
"Computer (this computer)", properties, advanced system settings, environment variable--system variable->path, in the last add the English state semicolon ";", paste the full path of the Jdk\bin directory into a semicolon, and finally click on three OK

Second, the common sense of software development:

1. What is software:
Commands and data that are organized according to specific rules that can accomplish a specific function

2. What is software development:
Development: The process of things from scratch
Software development: The process of making software

3. Classification of software:
Application software: Notepad, games, QQ, player, browser, etc.
System software: Operating system: Windows,linux,unix,mac, Android.
The role of the system software, in the management system hardware and software resources at the same time, to provide users with a visual interface, to the user to operate the computer provides a simple way

4. Human-Computer Interaction:
Graphically: With the help of the operating system
Command line mode: console input the appropriate instructions

Third, computer language:
1. Language: The medium of communication between people
2. Computer language:
The medium of communication between man and computer

People must learn computer language when they communicate with computers.

3. Common computer languages:
C,c++,c#,java ...

Iv. My first Java program:

Print Hello world!

Java Development tools: Notepad, Editplus,eclipse (MyEclipse)

Compile the Java program using the Javac tool and produce a. class file with the same file name (bytecode)

Steps:
1) write code;
2) Locate the Java file in the command line (use the CD to enter the folder)
3) Compile the Java file: Javac file name. java
4) Execute Program: Java class name (note: The Main method must be included in the class name)
Note: After a class is compiled, it produces a corresponding. class file with the same name as the class

Java SE Basics section