--- a/net/minecraft/server/AdvancementRewards.java
+++ b/net/minecraft/server/AdvancementRewards.java
@@ -98,7 +98,7 @@
                 }
 
                 public boolean getSendCommandFeedback() {
-                    return minecraftserver.worldServer[0].getGameRules().getBoolean("commandBlockOutput");
+                    return minecraftserver.worlds.get(0).getGameRules().getBoolean("commandBlockOutput"); // CraftBukkit
                 }
 
                 public void a(CommandObjectiveExecutor.EnumCommandResult commandobjectiveexecutor_enumcommandresult, int i) {
@@ -156,7 +156,7 @@
             return new AdvancementRewards(i, aminecraftkey, aminecraftkey1, customfunction_a);
         }
 
-        public Object deserialize(JsonElement jsonelement, Type type, JsonDeserializationContext jsondeserializationcontext) throws JsonParseException {
+        public AdvancementRewards deserialize(JsonElement jsonelement, Type type, JsonDeserializationContext jsondeserializationcontext) throws JsonParseException { // CraftBukkit - decompile error
             return this.a(jsonelement, type, jsondeserializationcontext);
         }
     }