Paper/nms-patches/WorldProvider.patch

--- a/net/minecraft/server/WorldProvider.java
+++ b/net/minecraft/server/WorldProvider.java
@@ -72,5 +72,5 @@
 
     public abstract boolean canRespawn();
 
-    public abstract DimensionManager getDimensionManager();
+    public DimensionManager getDimensionManager() { return this.f; } // CraftBukkit
 }