The temporary file names generated by MimeLauncher are not always
a valid file name. This results in that nothing is saved, and the user
in most cases is not notified that there was even a problem. The basic
problem lies in that the temp name is generated off of the specified URL.
In the case that I found, the URL is really a HTTP GET, and not really
a valid file name in any sense of the word. It seems this problem could
be easily solved if file names were not generated off of the URL, but
instead were along the lines of TIMESTAMP.MIMETYPE instead of tacking on a
timestamp onto the URL name for uniqueness. If it is still desirable to
have the uniqueness of the URL name in the temp file name, I propose to
use the hash value of the string instead of the string itself. The suggested
fix uses this technique to generate unique names.

Bug 4082093 indicates how to reproduce the problem:

To reproduce, in HotJava go to the viewer application page, and set
application/postscript to look for the Extension .ps and set the
Application to be: imagetool %s

Then go to an AnswerBook2 server, click on a book title, click on the print
icon, select a section to print, and then press the print button. You will
see imagetool come up, but with no text. An example URL to the print page
is:

        http://answers:8888/ab2/coll.47.4/BINARY/@Ab2PrintSelect