Decompilation of xercesImpl.jar hangs on this line:
Decompiling org/apache/xerces/dom/CoreDocumentImpl...

This can cause windup to hang if the package scan list causes it to scan this jar.

An upstream bug is filed here:
https://bitbucket.org/mstrobel/procyon/issue/215/decompiler-hangs-on-xercesimpl-test-jar

This upstream bug also appears to be similar:
https://bitbucket.org/mstrobel/procyon/issue/211/infinite-recursion