Compiling Java 7 code via Maven

java

java-7

maven

java-home

byAnton Shumikhin·Feb 2, 2025

To compile Java 7 with Maven, update the maven-compiler-plugin settings in pom.xml. Define both <source> and <target> as 1.7:

<plugin>
    <!-- "I am maven compiler, and I am not afraid of Java 7 :)" -->
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version>
    <configuration>
        <source>1.7</source> <!-- "Let's go vintage with Java 7!" -->
        <target>1.7</target>
    </configuration>
</plugin>

Setup environment: JAVA_HOME configuration

Check your JAVA_HOME environment variable points to your Java 7 JDK. In ~/.bash_profile or ~/.zshrc, add:

export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
# If Java could talk: "My home is now Java 7. Do visit sometime!"

Source this update to your profile:

source ~/.bash_profile
# or
source ~/.zshrc

For Windows, add this environment variable via System properties.

Keep up with JAVA_HOME: Confirmation

Double-check the JAVA_HOME setup by echoing it in the terminal:

echo $JAVA_HOME
# "Here's the address, here's the key, welcome home!"

Juggling with Java versions

When multiple Java versions give you a tough time, switch effortlessly with jEnv or sdkman:

# Using jEnv... Because following one path is too mainstream.
jenv add /path/to/java/home
jenv global oracle64-1.7

# Or sdkman... Because who doesn't love options!
sdk install java 7.0.262-zulu
sdk use java 7.0.262-zulu

They ensure that Maven uses the correct Java version.

Eliminate potential hiccups: Encoding and character support

To smooth out any encoding issues, set the global source file encoding in Maven to UTF-8:

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <!-- "Compilers speak many languages, UTF-8 is our lingua franca!" -->
</properties>

Investigating Java: Debugging compile version issues

Troubleshoot by checking the compiler version using Maven's debug mode:

mvn clean install --debug | grep 'Java home'
# "Maven wearing Sherlock's hat, getting to the root of things!"

Best practices for hassle-free version control

When configuring Java versions for Maven, consistency is king. Here’s how:

Plugin versions: Confirm to stay current

Ensure your maven-compiler-plugin is the latest version compatible with Java 7:

<plugin>
    <!-- "Latest and greatest, that's how we roll!" -->
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version> 
    <!-- ... -->
</plugin>

Module Consistency: Matching pom.xml files

Make sure all your project’s modules specify the same Java version in their pom.xml files:

<properties>
    <!-- "Let's dance to the same tune!" -->
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
</properties>