--- a/net/minecraft/server/WorldGenStronghold.java
+++ b/net/minecraft/server/WorldGenStronghold.java
@@ -67,7 +67,7 @@
 
     @Nullable
     @Override
-    public BlockPosition getNearestGeneratedFeature(World world, ChunkGenerator<? extends GeneratorSettingsDefault> chunkgenerator, BlockPosition blockposition, int i, boolean flag) {
+    public synchronized BlockPosition getNearestGeneratedFeature(World world, ChunkGenerator<? extends GeneratorSettingsDefault> chunkgenerator, BlockPosition blockposition, int i, boolean flag) { // CraftBukkit - synchronized
         if (!chunkgenerator.getWorldChunkManager().a(this)) {
             return null;
         } else {