Error when creating /nick Cmd

[sTiN55]

Hallo, wollte den /nick Command erstellen kommt jedoch immer ein Error. `package Commands;

import java.util.HashMap;

import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;

import de.domedd.betternick.BetterNick;
import de.domedd.betternick.api.betternickapi.BetterNickAPI;
import main.main;

public class nickCMD implements CommandExecutor {

public static HashMap<String, Player> nicked = new HashMap<String, Player>();
BetterNickAPI api = BetterNick.getApi();

@Override
public boolean onCommand(CommandSender sender,Command cmd,String label,String[] args){
	
	Player p = (Player) sender;
	
	if (p.hasPermission("sys.nick")) {
		Player player = p;
		if(args.length == 0) {
	        api.setRandomPlayerNickName(player, " ", " ");
	        api.setPlayerChatName(player, api.getNickName(player), " ", " ");
	        api.setPlayerDisplayName(player, api.getNickName(player), " ", " ");
	        api.setPlayerTablistName(player, api.getNickName(player), " ", " ");
	        api.setRandomPlayerSkin(player);
	    } else if(args.length == 1) {
	        String nickname = args[0];
	        api.setPlayerNickName(player, nickname, " ", " ");
	        api.setPlayerChatName(player, api.getNickName(player), " ", " ");
	        api.setPlayerDisplayName(player, api.getNickName(player), " ", " ");
	        api.setPlayerTablistName(player, api.getNickName(player), " ", " ");
	        api.setRandomPlayerSkin(player);
	    }
    } else {
      p.sendMessage(main.settcfg.getString("Settings" + ".Prefix") + "§cKeine Rechte!");
    }
	return false;
}

} [03:10:26 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'nk' in plugin DD-Selfmade v1.0
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:648) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.PlayerConnection.handleCommand(PlayerConnection.java:1399) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1234) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_201]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_201]
at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:748) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [spigot.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]
Caused by: java.lang.NullPointerException
at Commands.nickCMD.onCommand(nickCMD.java:27) ~[?:?]
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Spigot-dcd1643-e60fc34]
... 15 more
`

Skin wechseln geht nur /nick (/nk) nicht.

Grüße

[alextusinean]

Same error. Please help :)