[dep, 09Jul2007]
  
  My javaws-started Sun IM client dumped core in libzip after it had
  been running a few days.
  
  There is clearly a bug in libzip in that it dumps core, be it because
  it was given bad input or there is a flaw in its own logic. If the
  cause was indeed a corrupt jar file, there must be a second bug
  somewhere in the Java stack which resulted in the application being
  supplied with the corrupt jar file.

  Another data point: after I started the IM client last week, I
  started a second one while the first was still running. I seem to
  recall that this caused a re-download of the application.
  (Attempting that again today had the same effect, though I have been
  unable to reproduce the failure). One possibility is that this
  caused the corruption, which would be a serious bug in javaws.