How To Change Maven Java Version

7 min read Oct 15, 2024

Maven is a powerful build automation tool that helps Java developers manage dependencies, build projects, and run tests. It's a key part of the Java ecosystem, and a crucial skill for any Java developer. One of the common tasks you might encounter while using Maven is changing the Java version used for building your project. This can be necessary for a variety of reasons, such as using new language features, addressing compatibility issues, or simply aligning your project with the Java version used by other teams.

Why Change the Java Version in Maven?

Before diving into the specifics of how to change the Java version, let's understand why you might want to do it.

New Language Features: Java evolves with new releases, introducing exciting features and enhancements. If you want to leverage these features, you'll need to update the Java version in your Maven project.
Compatibility Issues: Sometimes, you might run into compatibility issues between your project's dependencies and the Java version you're currently using. Changing the Java version can resolve these conflicts and ensure smooth operation.
Project Standards: If your project is part of a larger system with specific Java version requirements, you'll need to change your Maven configuration to comply with those standards.

Methods to Change the Java Version in Maven

Let's explore the two common methods for changing the Java version used by Maven:

1. Using the `maven-compiler-plugin`:

This is the most direct way to specify the Java version for compilation. You'll modify the pom.xml file of your Maven project.

Steps:

Add the maven-compiler-plugin to your pom.xml file:
```
  org.apache.maven.plugins
  maven-compiler-plugin
  3.10.1
  
    11
    11
  
```
Explanation:
- groupId and artifactId: These identify the plugin.
- version: Specifies the version of the plugin.
- source and target: These are the key elements. They indicate the Java version used for compilation. In this example, we're using Java 11. Replace 11 with the desired Java version.
Run the Maven build:
```
mvn clean install
```
This will compile your project using the specified Java version.

2. Using the `JAVA_HOME` Environment Variable:

This approach sets the Java version globally for your system. It impacts all Maven projects, not just the one you're currently working on.

Steps:

Set the JAVA_HOME environment variable:
- Windows:
```
set JAVA_HOME=C:\Program Files\Java\jdk-11.0.12
```
- Linux/macOS:
```
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
```
Replace the path with the actual location of your Java installation.
Verify the change:

Open a new terminal and run:
```
echo $JAVA_HOME
```
This should display the updated path to your Java installation.
Run the Maven build:
```
mvn clean install
```

Important Considerations:

Java Version Availability: Ensure the desired Java version is installed on your system.
Multiple Java Versions: If you have multiple Java versions installed, be careful when setting the JAVA_HOME variable. Ensure you're pointing to the correct version.
IDE Compatibility: If you're using an IDE like Eclipse or IntelliJ, you may need to configure it to recognize the new Java version.

Troubleshooting

If you encounter problems after changing the Java version, here are some troubleshooting tips:

Check Maven Configuration: Ensure your pom.xml file contains the correct maven-compiler-plugin configuration, and that the Java version specified matches the one installed on your system.
Clear Cache: Clear Maven's cache with mvn clean to ensure it uses the new Java version.
Environment Variables: Verify that the JAVA_HOME environment variable is set correctly and is pointing to the right Java version.

Conclusion

Changing the Java version in Maven is essential for staying up-to-date with the latest Java features and ensuring project compatibility. Whether you use the maven-compiler-plugin or the JAVA_HOME environment variable, understanding the different methods and best practices will streamline your Java development workflow. Remember to carefully review your project's dependencies, and adapt the Java version accordingly for seamless integration and smooth compilation.