Hello my friend. First, sorry my english.. Second, on Byron's code, he appends some attributes to CatalogPieceOfFurniture and HomePieceOfFurniture (some attributes about mass). And he extends HomeDoorOrWindow and other in GazeeboDoorOrWindow and HomeGazeeboDoorOrWindow, appending particular information. He modify the FileUserPreferences class.
I'm reading the swing code now. When i finish whit that i'll write here the results.