How to Set the -source and -target Versions for Java Compiler in Maven Correctly?

What are the correct ways to set the -source and -target options for the Java compiler in Maven?

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

Setting the `-source` and `-target` options for the Java compiler in Maven is essential for ensuring your project is compiled with the correct Java version. This guide provides the steps to correctly configure these options and troubleshoot common issues.

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>${maven.compiler.source}</source>
                <target>${maven.compiler.target}</target>
            </configuration>
        </plugin>
    </plugins>
</build>

Causes

• Incorrectly specified Java version in the Maven properties.
• Maven compiler plugin is not included in the project's POM file.
• Inconsistent versions of Java installed on the system.

Solutions

• Update the `<properties>` section in your `pom.xml` file with the correct Java version.
• Ensure you are using the `maven-compiler-plugin` and specify the source and target versions correctly.
• Verify that the installed Java version matches the version specified in `pom.xml`.
• Use the command `mvn clean install` to ensure that Maven picks up the new configuration.

Mistake: Not including the `maven-compiler-plugin` in the `pom.xml`.

Solution: Make sure to add the `maven-compiler-plugin` in the `<build>` section.

Mistake: Setting incompatible Java versions in `maven.compiler.source` and `maven.compiler.target`.

Solution: Ensure both versions are compatible with each other and with your Java environment.

Mistake: Forgetting to use `${property_name}` for properties declared in the `<properties>` section.

Solution: Always surround property names with `${}` to reference them correctly.