The new plug-in touches the ImageIcon class in sun.plugin2.applet.Applet2Environment.initialize() as a workaround for bug 6482575, which has been fixed in 6u10. However, since the new plug-in needs to run on earlier releases, the workaround needs to stay in place, but should only be executed if the current Java version is less than 1.6.0_10.
Conditionalized the workaround for 6482575. Not possible to write a
regression test for this; according to -verbose:class logs, this class
is still being pulled in, likely for reasons being investigated under