Reverse dumpifs and jxe

I have two questions someone here might be so kind to help me with:

  1. I was wondering if it is possible to rebuild ifs (with mkifs) based on files extracted with dumpifs? I would appreciate a hint on how .build file should look like to have it done. Can I do it manually or I have to use QNX dev tools?
  2. Does anyone know what is the difference between .jar and .jxe? I know that j9 is used to run .jxe. Is there any tool to convert .jar to .jxe?

Thnx for help.