title: Refactor packages of a jar
body: <p>I am having some troubles with a jar, and I want to rename all clases to avoid conflicts, but I only have the final jar :(</p>
  
  <p>Classes in jar are in package as it:</p>
  
  <p>org.foundation  and I want to be available in another jar as</p>
  
  <p>org.foundation.oldversion</p>
  
  <p>Is there any tool to do it ?</p>
  
  <p>I don't want to decompile.</p>