[17:23:25] [Server thread/WARN]: java.lang.NoSuchMethodError: com.google.common.collect.Sets$SetView.iterator()Lcom/google/common/collect/UnmodifiableIterator;
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.trait.CommandTrait$PlayerNPCCommand.prune(CommandTrait.java:704)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.trait.CommandTrait.save(CommandTrait.java:333)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.npc.AbstractNPC.save(AbstractNPC.java:383)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.npc.CitizensNPC.save(CitizensNPC.java:192)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.npc.AbstractNPC.copy(AbstractNPC.java:143)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.npc.AbstractNPC.clone(AbstractNPC.java:136)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.commands.NPCCommands.copy(NPCCommands.java:495)
[17:23:25] [Server thread/WARN]:     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[17:23:25] [Server thread/WARN]:     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[17:23:25] [Server thread/WARN]:     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[17:23:25] [Server thread/WARN]:     at java.lang.reflect.Method.invoke(Method.java:498)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.command.CommandManager.executeMethod(CommandManager.java:159)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.command.CommandManager.execute(CommandManager.java:91)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.api.command.CommandManager.executeSafe(CommandManager.java:187)
[17:23:25] [Server thread/WARN]:     at net.citizensnpcs.Citizens.onCommand(Citizens.java:305)
[17:23:25] [Server thread/WARN]:     at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45)
[17:23:25] [Server thread/WARN]:     at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:146)
[17:23:25] [Server thread/WARN]:     at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:666)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1189)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:1001)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13)
[17:23:25] [Server thread/WARN]:     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[17:23:25] [Server thread/WARN]:     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:774)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:378)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:713)
[17:23:25] [Server thread/WARN]:     at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:616)
[17:23:25] [Server thread/WARN]:     at java.lang.Thread.run(Thread.java:748)