Problem with HA-JDBC and Tomat-6

[David Goodenough <david.goodenough@linkchoose.co.uk>]

I have an application running under Tomcat-6 (on a sid system with Sun
Java-6) which uses the java.util.prefs.FileSystemPreferences class.

This class assumes it can write to user.home, and in particular that it 
can create a directory called .java and create a file .userPrefs inside it.

But with the Debian Tomcat6, user.home points at /usr/share/tomcat6
which is not writable by the tomcat6 user.  Now I could overwride user.home
in the tomcat6 startup, but I would expect other problems if I did that.  I
could also (and this is what I have done just to get things going) create
a .java directory in /usr/share/tomcat6 and made it owned by tomcat6
so that it works.

What is the correct (Debian) solution?

David