Bukkit/CraftBukkit — pull request #929 by t7seven7t (2012-11-17 04:56:41+00:00)
Title: Update method in NMS code to be synchronized

Method a() in EntityTracker is causing Concurrents because its not synchronized with the other methods that also access the entity set b.

https://bukkit.atlassian.net/browse/BUKKIT-2691