/java-multi-release-jar

Primary LanguageJava

Java Multi-Release Jar (JEP-238)

Test project to see how to handle multi-release JAR with Maven. The project prints a simple output provided by different implementations depending on the Java Version.

Demo

To run manually. First build,

mvn package -DskipTests
java -jar target/java-multi-release-jar-0.1.0-SNAPSHOT.jar

Use sdkman! to configure different Java version. You should see that versions above 17 return with the 17 implementation, while older ones use the default.

Java Version Output

11.0.22-tem

Result: aaabbb (default, 11)

17.0.10-tem

Result: aaabbb (j17, 17)

21.0.2-tem

Result: aaabbb (j17, 17)

Learnt lessons

  • It has several drawbacks (specially for testing):

    • Intellij does not recognize the path and runs always default code from tests

    • The Java version used in compilation needs to be the highers possible, which can hide issues.

Overall, this seems an approach for "some" support for future Java versions, more than a solution for backward compatibility.

Resources used: