Set Java environment variables to allow the program to run properly

How to configure Java environment variables to run the program correctly, specific code examples are required

Java is a popular programming language used to develop cross-platform applications. In order to ensure that Java programs run correctly, correct environment variables need to be configured. This article will introduce how to configure Java environment variables in Windows and Linux systems, and provide specific code examples.

1. Windows system configuration Java environment variables

1. Download and install the Java Development Kit (JDK): Visit the Oracle official website, find the appropriate version of JDK and download and install it.
2. Open the "Control Panel": Click the "Start" menu and select "Control Panel".
3. Enter "System" settings: Find and click "System" in the control panel.
4. Click "Advanced System Settings": In the system window, click "Advanced System Settings" on the left.
5. Open the "Environment Variables" dialog box: Under the "Advanced" tab, click the "Environment Variables" button.
6. Set user variables: Under the "User Variables" area, click the "New" button. Enter the variable name "JAVA_HOME", and the variable value is the JDK installation path, such as "C:Program FilesJavajdk1.8.0_251".
7. Modify system variables: Under the "System Variables" area, find the variable named "Path" and click the "Edit" button. In the pop-up editing dialog box, click the "New" button and enter "%JAVA_HOME% in".
8. Verify the configuration result: Open the command prompt (press the Win R key, enter "cmd" and press the Enter key), enter the "java -version" command. If the environment variables are configured correctly, the version information of the Java installation will be displayed.

2. Linux system configuration Java environment variables

1. Download and install the Java Development Kit (JDK): Visit the Oracle official website, find the appropriate version of JDK and download and install it.
2. Open the terminal: In Linux system, open the terminal.

3. Edit configuration file: Enter the following command to edit the bash configuration file:

   sudo nano /etc/profile

4. Set environment variables: In the opened configuration file, finally add the following content:

   export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
   export PATH=$PATH:$JAVA_HOME/bin

   Note: Replace "/usr/lib/jvm/java-8-openjdk-amd64" with the actual installation path of the JDK.

5. Save and exit the configuration file: Press Ctrl X, then press Y to save changes.

6. Update configuration: Enter the following command to make the configuration file take effect:

   source /etc/profile

7. Verify the configuration result: Enter the "java -version" command in the terminal. If the environment variables are configured correctly, the version information of the Java installation will be displayed.

Through the above steps, you have successfully configured Java environment variables. Now you can write and run Java programs. The following is a simple Java program example:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Save the above code as HelloWorld.java, and use the command line to compile and run:

javac HelloWorld.java
java HelloWorld

If the correct Java environment variables are configured, you will See the output "Hello, World!".

Summary:

Configuring Java environment variables is an important step to ensure the correct operation of Java programs. This article provides detailed steps for configuring Java environment variables in Windows and Linux systems and provides a simple Java program example. I hope this article will help you to successfully configure Java environment variables and write excellent Java programs.

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