If the EMBED tag is not closed properly, when the plugin is processing the EMBED applet info, the browser process gets killed with a "bus error" in the command line.
for example:

   <EMBED type="application/x-java-applet;version=1.2"
       java_CODE = "IsClassAvailable.class"
       WIDTH = 400 HEIGHT = 50

       className = "com.sun.java.swing.JLabel"
       pkgName = "Swing 1.0.3"
   > ************ { IF THIS GT IS REMOVED THEN THE BROWSER CRASHES } ******
   </EMBED>