Yes, I know that I cannot do that. But I don't know how to use the type HomeTexture.
That is my problem. I don't understand if I should create a variable that is HomeTexture. eg.

TextureImage firstTexture = preferences.getTexturesCatalog().getCategories().get(0).getTexture(0);

Home Texture newHomeTexture = new HomeTexture(firstTexture texture); (something like that)

Parallelogram_Room.setFloorTexture(newHomeTexture);

But the thing is that I don't understand how to use the default libraries of Sweethome3D.

Like, if I want Beige_Tiles, how do I select them?