If you open hudson.plugins.jabber.im.transport.JabberPublisher.xml you will notice that the jabber password is stored in cleartext :

 

  <hudson.plugins.jabber.im.transport.JabberPublisherDescriptor>
  [...]
 	<hudsonPassword>Protext_the_innocent</hudsonPassword> 

Other components (ldap bind password, svn) have a hash mechanism as far as I can see, not sure if there is a common library to use but it would be a nice addition.

Thank you !