Java 9模块和uber-jar

Question

When developing Java libraries we're currently using the Apache Maven Shade Plugin to hide internal dependencies on other libraries (jars) by renaming their package names.

Is it possible to hide these internal library-dependencies by using the Java 9 module system and not exporting the name of the internally used libraries? Ie:

1. Both module A and B include, but does not export, class org.codehaus.jackson.map.ObjectMapper (included using eg Maven Shade plugin) with different versions for the class
2. Module A uses module B

Will each module still use its implementation org.codehaus.jackson.map.ObjectMapper?

I believe it should by so, but I have found no documentation explicitely confirming this, nor any texts / examples recommending this approach for this quite usual versioning issue.

Answer 1

This issue is described as http://openjdk.java.net/projects/jigsaw/spec/issues/#MultiModuleExecutableJARs and there's no support for it yet. In case all dependencies are modules, it would make sense to use jlink to solve this. But as long as there is at least one non-module, there's no solution available yet. This is something that needs to be solved within the JDK/JRE. It is still a valid case, so I would suggest to ask this question the at jigsaw-dev mailinglist and refer to #MultiModuleExecutableJARs