Step-by-step explanation of how to set Java environment variables

Java environment variable configuration step analysis

Introduction:
Java is a widely used programming language used to develop various types of applications. In order to use and compile Java programs correctly, you need to configure the correct Java environment variables. This article will introduce the steps to configure Java environment variables in detail and provide specific code examples.

1. Download and install Java Development Kit (JDK)
First, you need to go to the official Java website (https://www.oracle.com/java/technologies/javase-jdk11-downloads.html) Download the Java Development Kit (JDK) installation package suitable for your operating system and install it according to the prompts.

2. Configure the JAVA_HOME variable

1. Open the system environment variable configuration window, which can be found by entering "environment variables" in the Windows search bar.
2. Under User Variables, click the "New" button.
3. In the "Variable Name" input box, enter "JAVA_HOME" (without quotation marks).
4. In the "Variable Value" input box, enter the installation path of the JDK, for example: "C:Program FilesJavajdk11.0.1".
5. Click the "OK" button to save the variable configuration.

3. Configure the Path variable

1. In the system environment variables window, find the "Path" variable and click the "Edit" button.

2. At the end of the "Variable Value" input box, add ";%JAVA_HOME% in;%JAVA_HOME%jre in".

   • Note: If other paths already exist in Path, please separate the original path and the newly added path with a semicolon ";".
3. Click the "OK" button to save the variable configuration.

4. Verify whether the environment variables are configured successfully

1. Open the command prompt window (cmd).
2. Enter the "java -version" command and press the Enter key.
3. If the Java version information is displayed correctly, it means that the environment variables have been successfully configured.

Code example:
The following is a code example using Java environment variables to write a simple "Hello World" program.

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

Save the above code as a file with the extension .java (such as HelloWorld.java), and then switch to the file in the command prompt window The folder where it is located, and execute the following command to compile and run:

javac HelloWorld.java
java HelloWorld

If no errors occur and "Hello World!" is correctly output, it means that the Java environment variable configuration and code compilation and running are successful.

Summary:
Through the above steps, we successfully configured the Java environment variables, and successfully compiled and ran a simple Java program. Properly configuring Java environment variables is very important for developing and running Java applications. I hope this article will help you understand and configure Java environment variables.

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