Implements a World UID.

By: Rigby <rigby@onarandombox.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -490,6 +490,16 @@ public final class CraftServer implements Server {
         return worlds.get(name.toLowerCase());
     }
 
+    public World getWorld(long uid) {
+        for (String worldName : worlds.keySet()) {
+            org.bukkit.World world = worlds.get(worldName);
+            if (world.getUID() == uid) {
+                return world;
+            }
+        }
+        return null;
+    }
+
     public void addWorld(World world) {
         worlds.put(world.getName().toLowerCase(), world);
     }

paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -395,10 +395,15 @@ public class CraftWorld implements World {
         return world.worldData.name;
     }
 
+    @Deprecated
     public long getId() {
         return world.worldData.getSeed();
     }
 
+    public long getUID() {
+        return world.worldData.getWorldUID();
+    }
+
     @Override
     public String toString() {
         return "CraftWorld{name=" + getName() + '}';