[14:27:10 INFO]: SzymoonPL issued server command: /zaloguj
[14:27:10 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'zaloguj' in plugin NL_Hu
b v0.1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Spigot-5
4ec0b8-be9ef98]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot.jar:git-
Spigot-54ec0b8-be9ef98]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.dispatchCommand(CraftServer.java:650) ~[spigo
t.jar:git-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.PlayerConnection.handleCommand(PlayerConnection.java:1353)
[spigot.jar:git-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:1188) [spigot.jar:
git-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:gi
t-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git
-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-
Spigot-54ec0b8-be9ef98]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_121]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_121]
        at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:46) [spigot.jar:git-Spigot-54ec0b8
-be9ef98]
        at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:747) [spigot.jar:git
-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot.jar:git
-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:678) [spigot.jar:git
-Spigot-54ec0b8-be9ef98]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:576) [spigot.jar:g
it-Spigot-54ec0b8-be9ef98]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_121]
Caused by: java.lang.NullPointerException
        at pl.SzymoonDev.NL_Hub.commands.ZalogujCommand.onCommand(ZalogujCommand.java:19) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Spigot-5
4ec0b8-be9ef98]
        ... 15 more