Composition in Mindcraft 

We can find the source code for this Immersive Railroad application at https://github.com/cam72cam/ImmersiveRailroading.

Minecraft could have chosen to implement their world building UI exclusively with FP techniques by currying partial applications, but when we look closer we find more of an imperative implementation. Though generics are used:

// cam72cam.immersiverailroading.render.TileSteamHammerRender
public class TileSteamHammerRender extends TileEntitySpecialRenderer<TileSteamHammer> {   
   private List<String> hammer;
   private List<String> rest;