Fellow Linux users affected by the same problem, I have good news for you: I have managed to get the cute new XXE applet demos to run (at least they do now for me).
The critical issue seems to be that you must be using the "next generation Java[TM] plug-in" and not the usual Java plug-in. It is true that this requirement is mentioned at http://www.xmlmind.com/xmleditor/xxe_applet.html, but it is not so easy to find out how to *select* the New plug-in, as just *installing* a recent JRE is not sufficient. Windows seems to offer a selection through the Java Console and even makes the New plug-in the default. Some Linux flavours, reportedly Gentoo, might allow the user to choose among the Java plug-in versions that the installed JRE offers. Ubuntu 8.04, however, required me to take a few manual steps (following the hints at https://jdk6.dev.java.net/plugin2/#INSTALLATION ): 1 - Quit Firefox. 2 - Install a very recent JRE (1.6.0_10 or above) into /opt/java, aside the Ubuntu 8.04 package system (which unfortunately does not provide any JRE newer than 1.6.0_07). 3 - Remove any older Java plugins (or symlinks to them) from the Firefox plugins directory (e.g. /usr/lib/firefox-3.0.11/plugins), then create a symlink from the New plug-in, a.k.a. next generation plug-in, into the Firefox plugins directory. Note: At least with JRE 1.6.0_14, the next generation Java plug-in is *not* located in the "plugin" subdirectory of the JRE installation directory, but inside the "lib" subdirectory, and is called "libnpjp2.so". So for me, selecting the new Java plug-in instead of the conventional one came up to do: cd /usr/lib/firefox-3.0.11/plugins sudo rm libjavaplugin_oji.so sudo ln -s /opt/java/jre1.6.0_14/lib/i386/libnpjp2.so . 4 - Restart Firefox. It will automatically use the Java plug-in from its "plugins" directory. 5 - Open http://www.xmlmind.com/xmleditor/_applet/viewer.html , sit back and watch the beautiful XXE viewer applet running. :-) Hussein, would it be possible to enrich the requirements section of http://www.xmlmind.com/xmleditor/xxe_applet.html with a reference to https://jdk6.dev.java.net/plugin2/#INSTALLATION where the essential instructions for installing and selecting the New Java plug-in can be found? Yves
