Java4android "3" Java environment variable JRE

1. The purpose of the PATH environment variable configuration
2. CLASSPATH environment variable configuration of mud
3. What support is provided by the Java JRE

These two files can be found when the 1:PATH environment variable is used to execute the Java.exe and Javac.exe commands. Java is mostly used by these two executable files. The value previously configured for the PATH environment variable is the path to the JDK installation.

The 2:CLASSPATH environment variable is the location where the class file and source file can be found when the command is executed. For example, execute Java hello.class, and Javac Hello.java (the following extensions are written for zone classification files and source files)

The environment variables for the previously configured classpath are.; is the meaning of the current path. For example, my hello.class in the E-disk Gmzjava below, execute this class file can be in the cmd inside such: First typing CD and then directly put Gmzjava folder into cmd, enter, so directly into the Gmzjava directory, then the hint is e:\ Gmzjava> this time enter Java Hello then the Hello.class file will be executed. Java.exe is found through path, hello.class through Classpath, which is the path under the current command line. This is e:\gmzjava>.

The 3:java JRE is the Java operating environment. Mainly include

1 Java Virtual machine

The purpose of the virtual machine is to have Javac compiled. Class code can be used across platforms. That is, the Java source code is compiled into a. class file by Javac, but the. class file can run on the platform of Windows, Apple, and whatever, because the Java virtual machine translates. class files into code that can be used by each platform. The virtual machine is also a translation work, without the programmer to consider the Java code written out can be a different platform to run.

2 Java Core class files

3 Other supporting documents