Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans package.
Please see XMLEncoder.
Returns an instance of the UI delegate for the specified component.
Each subclass must provide its own static createUI
method that returns an instance of that UI delegate subclass.
If the UI delegate subclass is stateless, it may return an instance
that is shared by multiple components. If the UI delegate is
stateful, then it should return a new instance per component.
The default implementation of this method throws an error, as it
should never be invoked.