On: InternalFrameInternalFrameTitlePaneInternalFrameTitlePaneMaximizeButtonPainter

[javajosh]

You probably won't see RouterMessageHeader.toXMLString() in the calling code though. You'd see:

  RouterMessageHeader foo = new RouterMessageHeader();
  foo.toXMLString();

There are other ways for foo to be derived, of course, and in many of them you never need to reference the ReferenceMessageHeader class name.