Java Development Environment Building

I. JDK and JRE

JDK (Java Development Kit) Java development tool that contains all the components that develop Java programs, including the JRE

JRE (Java Runtime Environment) Java Runtime Environment , if you want to run Java programs, you need JRE support

Common components:

Src.zip Java is an open source language, and its source code is in this compressed package

Rt.jar Java's underlying core class library, the class we use when we write Java programs is in this JAR package

Javac.exe compiler to compile the. Java source code into a. class file

Java.exe virtual machines, tools for running Java programs

Jar.exe tool to make a class file into a jar package

Javadoc.exe tools to generate help documents

Environment variable: Environment variable refers to some parameters used in operating system to specify operating system environment.

Java_home: in the environment variable new java_home specified to the JDK installation directory, some JAVA installation software run will look for Java_home

Path :

If you want to run a program in any directory, we need to configure the path where the program is located in the PATH environment variable.

Usually we will configure the Javac.exe directory to path, because we need to be able to compile Java source files in any directory.

After the configuration is complete, you can enter the Javac test at the command line if the explicit Help information is configured successfully.

Configuration:%java_home%\bin;

classpath:

The path of the load class when the Java virtual Runtime is running. JDK5 is not configured to default to the current directory ".". Manual configuration is required if you use JDK1.4 or the following versions.

No configuration is required, and all class files under the current directory are loaded by default.

Three, configuration mode: My Computer

Right-click My Computer – Properties – Advanced – Environment variables

Find the variable you want to modify to modify its value, which is permanently valid

Note The post-configuration check:

Compiler version viewing mode: Javac–version

Virtual machine version viewing mode: Java–version

Java Development Environment Building