[19:08:11 INFO]: viet1 issued server command: /xc
[19:08:11 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'xc'
in plugin clear_chat v1.0
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[cra
ftbukkit.jar:git-Bukkit-0ebb9c7]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:14
0) ~[craftbukkit.jar:git-Bukkit-0ebb9c7]
        at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServ
er.java:625) ~[craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.PlayerConnection.handleCommand(PlayerCo
nnection.java:1299) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.jav
a:1159) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(SourceFile:37) [craf
tbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.PacketPlayInChat.a(SourceFile:9) [craft
bukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.PlayerConnectionUtils$1.run(SourceFile:
13) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [
?:1.8.0_101]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_101]
        at net.minecraft.server.v1_10_R1.SystemUtils.a(SourceFile:45) [craftbukk
it.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:
690) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:
360) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:
646) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.jav
a:550) [craftbukkit.jar:git-Bukkit-0ebb9c7]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_101]
Caused by: java.lang.ArrayIndexOutOfBoundsException: 0
        at me.chat.clear.XoaChat.onCommand(XoaChat.java:37) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[cra
ftbukkit.jar:git-Bukkit-0ebb9c7]
        ... 15 more