islandworld

[SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'islandev' in plugin SkyLand v1.2.5
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:168)
	at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:510)
	at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:880)
	at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:826)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:808)
	at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:44)
	at net.minecraft.server.NetworkManager.b(NetworkManager.java:276)
	at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:109)
	at net.minecraft.server.ServerConnection.b(SourceFile:35)
	at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:579)
	at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:213)
	at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:475)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:407)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
Caused by: java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:894)
	at java.util.HashMap$EntryIterator.next(HashMap.java:934)
	at java.util.HashMap$EntryIterator.next(HashMap.java:932)
	at pl.islandworld.commands.IslandDev.commandPurge(IslandDev.java:220)
	at pl.islandworld.commands.IslandDev.onCommand(IslandDev.java:140)
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
	... 15 more