The most effective way would be to ask your HP sales rep to give you the Java Add-in CD and an evaluation license for 2 weeks and make your own experience.
Nevertheless, here are 2 attachments of properties the GUI spy sees when spying on a window and object of a SwingSet-Demo-application.
Plus you can call all Java methods the object owns (this might give you even some more properties, if your objects hava some get...-methods).
No, it is not. Depending on the GUI objects you are using, WR treats Java objects like any other objects and identifies them by class and label (if both values are available and are sufficient for a unique identification).
Windows have an additional obligatory property: mic_if_handles_windows (I guess that's an internal property of the Java-AddIn that tells WR that this window is a Java-window).
But again: In menu Tools > GUI Map Configuration you can configure TOOLKIT_class as an obligatory property for your objects (when learning new objects). It's not default, but you can change it to default...