Configuring Java Environment Variables (Windows OS)

Updated on 2022-02-24 GMT+08:00

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Right-click Computer and choose Properties.

Figure 1 Properties
Select Advanced system settings.

Figure 2 System
In the System Properties dialog box, choose Advanced > Environment Variables.

Figure 3 System Properties dialog box
Configure the system variables. Configure the following three variables: JAVA_HOME, Path, and CLASSPATH (where the variable names are case-insensitive). If a variable name exits, click Edit. If a variable name does not exist, click New to create one. Generally, the Path variable exists, and the JAVA_HOME and CLASSPATH variables need to be added.

Figure 4 Environment Variables dialog box

JAVA_HOME indicates the JDK installation path and is set to C:\ProgramFiles\Java\jdk1.8.0_45. This path contains the lib and bin files.

Figure 5 Creating JAVA_HOME

Path enables the system to recognize a Java command in any path. If the Path variable exists, add a path at the end of the variable value. Configuration example: ;C:\Program Files\Java\jdk1.8.0_45\bin;C:\Program Files\Java\jdk1.8.0_45\jre\bin

Two paths need to be separated by using a semicolon (;).

Figure 6 Setting Path

CLASSPATH specifies the path of loaded Java classes (class or lib). Java commands can be identified only if they are contained in the class path. Configuration example: .;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar

NOTE:

The path starts with a dot (.), indicating the current path.

Figure 7 Setting CLASSPATH
Restart the OS for the environment variables to take effect.
Choose Start > Run, enter cmd, and run the following commands: Java -version, java, and javac. If the commands can be run, the environment variables are set successfully.

Figure 8 Verifying environment variables