Missing main level `module-info.class` in the Maven artifact

[envas]

The jar file published on Maven is missing module-info. It raises the runtime error:

java.lang.module.FindException: Module tools.jackson.core not found, required by tools.jackson.databind

when using Java Platform Module System (JPMS) => unusable for building applications with modules. (databind is OK).

See: https://docs.oracle.com/en/java/javase/11/docs/specs/jar/jar.html#:~:text=ordinary%20JAR%20file.-,Modular%20multi%2Drelease%20JAR%20files,directly%20in%20a%20versioned%20directory.

[pjfanning]

The file is in META-INF/versions/17/module-info.class (jackson-core-3.1.0.jar)

[envas]

When I compile the original jar with JDK25 I get the error about missing module-info.class. When I moved (by hand) the module-info.class into the root of the jar the runtime error disappeared.

I am not familiar with multi MRJAR but is the location META-INF/versions/17/ not valid only for JDK17? There is no module info in other META-INF/versions/... directories.

[pjfanning]

@envas you own long oracle link above says: or directly in a versioned directory

17 means 17 and above.
if you have a 21 versioned class than that overrides the 17 and above one for 21 and above.

We do releases with Java 17 build. I'm not sure if the Java 25 build produces what you want but if you don't want to use the jars that we publish to Sonatype then I would recommend building the jar with Java 17.

[pjfanning]

If you want assistance, please provide a POC. A github project is probably best. Please don't zip something and attach it here.

[cowtowncoder]

Also, see #1562. Jackson-core 3.1.1 should have module-info.class at root.