How to configure maven-compiler-plugin to java 17

Configuring Maven Compiler Plugin for Java 17

Learn how to effectively configure the maven-compiler-plugin to ensure your Java projects compile correctly with Java 17, leveraging its new features and improvements.

Upgrading Java projects to newer versions often involves updating build configurations. When moving to Java 17, a long-term support (LTS) release, it's crucial to correctly set up your Maven build to compile your source code against the new language features and APIs. This article will guide you through the necessary steps to configure the maven-compiler-plugin for Java 17, ensuring a smooth transition.

Understanding the maven-compiler-plugin

The maven-compiler-plugin is a core plugin in Maven responsible for compiling the source code of your project. It uses the javac compiler from your installed Java Development Kit (JDK). To compile for a specific Java version, you need to tell this plugin which source and target versions to use. Failure to do so can lead to compilation errors or the project being compiled with an older Java version, preventing you from using newer language features.

<project>
    ...
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <configuration>
                    <source>17</source>
                    <target>17</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
    ...
</project>

Minimal configuration for maven-compiler-plugin to use Java 17

Configuring Source and Target Versions

The primary settings for the maven-compiler-plugin are <source> and <target>. The <source> parameter specifies the Java language version of your source code, while <target> specifies the version of the generated bytecode. For Java 17, both should generally be set to 17.

It's also a good practice to define these versions as properties in your pom.xml for better maintainability and consistency across multiple plugins or modules. This allows you to change the Java version in one place.

<project>
    ...
    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <!-- Configuration inherited from properties -->
            </plugin>
        </plugins>
    </build>
    ...
</project>

Recommended approach using properties for Java source and target versions

Maven Compilation Process with Java 17 Configuration

Ensuring Plugin Version Compatibility

It's important to use a version of maven-compiler-plugin that officially supports Java 17. Apache Maven recommends using version 3.8.0 or newer for Java 9+ compatibility, and specifically 3.10.1 or later for full Java 17 support. While older versions might work, using the latest stable release (e.g., 3.11.0 or newer) is always recommended for bug fixes and improved performance.

To check the latest version, refer to the official Maven Compiler Plugin documentation.

1. Step 1

Open your project's pom.xml file.

2. Step 2

Locate the <properties> section and ensure maven.compiler.source and maven.compiler.target are set to 17.

3. Step 3

Find the maven-compiler-plugin configuration within the <build> -> <plugins> section.

4. Step 4

Verify that the <version> of the maven-compiler-plugin is 3.11.0 or newer.

5. Step 5

If the <source> and <target> elements are explicitly defined within the plugin's <configuration>, update them to 17.

6. Step 6

Run mvn clean install from your terminal to compile and package your project.