fixed environments

src/main/java/net/minecraft/server/World.java

@@ -47,7 +47,7 @@ public class World implements IBlockAccess {
     public int spawnMonsters;
     public Random random = new Random();
     public boolean s = false;
-    public final WorldProvider worldProvider;
+    public WorldProvider worldProvider; // Craftbukkit - remove final
     protected List u = new ArrayList();
     public IChunkProvider chunkProvider; // CraftBukkit - protected -> public
     protected final IDataManager w;

src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -26,7 +26,7 @@ import org.bukkit.World;
 
 public class CraftWorld implements World {
     private final WorldServer world;
-    private final Environment environment;
+    private Environment environment;
     private final CraftServer server;
     private final ChunkProviderServer provider;
     private HashMap<Integer,CraftChunk> unloadedChunks = new HashMap<Integer, CraftChunk>();
@@ -37,12 +37,8 @@ public class CraftWorld implements World {
         this.world = world;
         this.server = world.getServer();
         this.provider = world.chunkProviderServer;
-
-        if (world.worldProvider instanceof WorldProviderHell) {
-            environment = Environment.NETHER;
-        } else {
-            environment = Environment.NORMAL;
-        }
+        
+        environment = Environment.getEnvironment(world.worldProvider.dimension);
 
         server.addWorld(this);
     }
@@ -443,6 +439,13 @@ public class CraftWorld implements World {
     public Environment getEnvironment() {
         return environment;
     }
+    
+    public void setEnvironment(Environment env) {
+        if (environment != env) {
+            environment = env;
+            world.worldProvider = WorldProvider.a(environment.getId());
+        }
+    }
 
     public Block getBlockAt(Location location) {
         return getBlockAt(location.getBlockX(), location.getBlockY(), location.getBlockZ());