Implements World UID.

src/main/java/org/bukkit/Server.java

@@ -217,6 +217,14 @@ public interface Server {
      */
     public World getWorld(String name);
 
+    /**
+     * Gets the world from the given Unique ID
+     *
+     * @param uid Unique ID of the world to retrieve.
+     * @return World with the given Unique ID, or null if none exists.
+     */
+    public World getWorld(long uid);
+
     /**
      * Reloads the server, refreshing settings and plugin information
      */

src/main/java/org/bukkit/World.java

@@ -363,14 +363,23 @@ public interface World {
      */
     public String getName();
 
+    /**
+     * Gets the Unique ID of this world
+     *
+     * @return Unique ID of this world.
+     */
+    public long getUID();
+
     /**
      * Gets a semi-unique identifier for this world.
      *
      * While it is highly unlikely that this may be shared with another World,
      * it is not guaranteed to be unique
      *
+     * @deprecated Replaced with {@link #getUID()}
      * @return Id of this world
      */
+    @Deprecated
     public long getId();
 
     /**