Comment 21 for bug 344705

I can confirm that after the update to 6b14-1.4.1-0ubuntu6, and purging sun-java6-plugin, my test cases work:
* http://java.com/en/download/help/testvm.xml
* http://java.sun.com/applets/other/Bubbles/index.html works
* http://www.jigzone.com/puzzles/daily-jigsaw works

If I then install sun-java6-plugin, BOTH plugins are loaded, indicating that:
- firefox 3 is seeing the two plugins via different paths
- the sun plugin is providing alternatives that the icedtea plugin doesn't

The sun plugin was first when I restarted firefox immediately after installing sun-java6-plugin. When I then reset the alternatives for the openk, the icedtea plugin appeared first. At that stage, I checked /etc/alternatives/*javaplugin*, and get the following list of alternatives, only one of which points to the icedtea plugin.
tim@zaphod:~$ ls -l /etc/alternatives/*javaplugin*
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/firefox-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/iceape-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/iceweasel-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/midbrowser-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/mozilla-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so
lrwxrwxrwx 1 root root 58 2009-04-13 11:21 /etc/alternatives/xulrunner-1.9-javaplugin.so -> /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/IcedTeaPlugin.so
lrwxrwxrwx 1 root root 49 2009-04-13 11:21 /etc/alternatives/xulrunner-javaplugin.so -> /usr/lib/jvm/java-6-sun/jre/lib/amd64/libnpjp2.so

Checking firefox/xulrunner java plugin references gives:
tim@zaphod:~$ ls -l /usr/lib/xulrunner*/plugins/*java* /usr/lib/firefox*/plugins/*java*
lrwxrwxrwx 1 root root 45 2009-03-19 07:15 /usr/lib/xulrunner-1.9.0.8/plugins/libjavaplugin.so -> /etc/alternatives/xulrunner-1.9-javaplugin.so
lrwxrwxrwx 1 root root 45 2009-03-19 07:15 /usr/lib/xulrunner-addons/plugins/libjavaplugin.so -> /etc/alternatives/xulrunner-1.9-javaplugin.so
lrwxrwxrwx 1 root root 41 2009-04-13 11:17 /usr/lib/xulrunner/plugins/libjavaplugin.so -> /etc/alternatives/xulrunner-javaplugin.so
lrwxrwxrwx 1 root root 39 2009-04-13 11:17 /usr/lib/firefox/plugins/libjavaplugin.so -> /etc/alternatives/firefox-javaplugin.so
tim@zaphod:~$

So xulrunner code appears to be searching for plugins in at least two places (and finds different end targets).

This is a separate bug (may actually be two bugs:
  openjdk/icedtea plugin failing to provide the full set of alternatives
  xulrunner searching multiple places for its plugins