I haven't done any updates to the javadjvu viewer in a long time. With the state of Java, I tend to question the usefulness of such development.

e.g. In recent months there have been several major security alerts that have forced users on all platforms to disable their java plugins. Even without that, the major advantage of a java applet is to allow cross-platform support. But now for several years, java AWT plug-in support has been broken on most Linux distributions. For example, it didn't work at all for Fedora 15, Fedora 16. I never tried with Fedora 17. I see now the applet finally works again in Fedora 18. I had several reports of Ubuntu releases having the same problem, which makes sense since they use the same versions of java.

BTW. The viewer does use progressive rendering. So rendering starts as soon as there is sufficient data available. However, I'm sure it could be improved to work better.