Forum: JRuby persistent on parent classes enough?

I noticed that if I do:
  JComponent.__persistent__=true

I still get this warning:
warning: instance vars on non-persistent Java type
Java::JavaxSwing::JButton (http://wiki.jruby.org/Persistence)

even though JButton is a child class of JComponenent.  I assume this is
expected and there's nothing I can do about it?  (Just wondering,
thanks).
-roger-