title: How do I modify a look and feel system class such as com.sun.java.swing.plaf.windows.WindowsTableHeaderUI
body: <p>I need to make a change to this class, there is no way for me to just subclass in normal way. So I can modify the java file (or make a copy of it) but how do I get my Swing application to use this version instead of the one provided by the Java runtime?</p>
  <p>What I am trying to do is make a copy of  com.sun.java.swing.plaf.windows.WindowsTableHeaderUI and fix it, so I cant just create a copy of the class sand put it into my own pacakage hierachy as I dont have access to many of the classes referred to in the class (such as XPStyle) so how do i replace the system class?</p>