[05:53:02] [Server thread/ERROR]: Encountered an unexpected exception
java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextNode(HashMap.java:1437) ~[?:1.8.0_111]
        at java.util.HashMap$KeyIterator.next(HashMap.java:1461) ~[?:1.8.0_111]
        at net.minecraft.server.v1_10_R1.EntityTracker.updatePlayers(EntityTracker.java:176) ~[survival-1.10.2.jar:git-Spigot-de459a2-51263e9]
        at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:816) ~[survival-1.10.2.jar:git-Spigot-de459a2-51263e9]
        at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:400) ~[survival-1.10.2.jar:git-Spigot-de459a2-51263e9]
        at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:668) ~[survival-1.10.2.jar:git-Spigot-de459a2-51263e9]
        at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:567) [survival-1.10.2.jar:git-Spigot-de459a2-51263e9]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_111]
[05:53:02] [Server thread/ERROR]: This crash report has been saved to: /home/minecraft/Survival/./crash-reports/crash-2016-12-09_05.53.02-server.txt