Timer - Creating

Hi! I with the help of two people (Woobie & fireblast709) created, but they have created, the timer counting seconds and adds 1 second 1 lvl exp. Unfortunately, this timer is bugged, when you type / timer is added to the ArrayList but if another person enters / timer will be added, but the timer will not work, and others will be able to control (start / stop). Do you know the solution to this problem?

Code:

package MaTyyy.Perla;
 
import java.util.ArrayList;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.plugin.java.JavaPlugin;
 
public class Perla extends JavaPlugin  implements Listener{
    public boolean addLevels = false;
    public ArrayList<String> xpToPlayers = new ArrayList<String>();
    public String x;
  public void onEnable()
  {
      getServer().getPluginManager().registerEvents(this, this);
      getServer().getScheduler().scheduleSyncRepeatingTask(this, new Runnable()
      {
       
          @Override
          public void run()
          {
                    if(addLevels)
              {
                      for(String player : xpToPlayers)
                      {
                          Player p = Bukkit.getPlayer(player);
                          if(p == null)
                          {
                             
                              continue;
                          }
                        p.setLevel(p.getLevel() + 1);
                        p.setExp(0);
                      }
                 
              }
             
          } 
      }, 0L, 20L);
      getServer().getScheduler().scheduleSyncRepeatingTask(this, new Runnable()
      {
       
          @Override
          public void run()
          {
                    if(addLevels)
              {
                      for(String player : xpToPlayers)
                      {
                          Player p = Bukkit.getPlayer(player);
                          if(p == null)
                          {
                             
                              continue;
                          }
                        p.setExp((float) (p.getExp() + 0.25));
                      }
                     
              }
             
          } 
      }, 0L, 10L);
      getServer().getScheduler().scheduleSyncRepeatingTask(this, new Runnable()
      {
       
          @Override
          public void run()
          {
                    if(addLevels)
              {
                      for(String player : xpToPlayers)
                      {
                          Player p = Bukkit.getPlayer(player);
                          if(p == null)
                          {
                   
                      continue;
                  }  p.setExp((float) (p.getExp() + 0.25));
                      }
              }
             
          } 
      }, 0L, 13L);
      getServer().getScheduler().scheduleSyncRepeatingTask(this, new Runnable()
      {
       
          @Override
          public void run()
          {
                    if(addLevels)
              {
                      for(String player : xpToPlayers)
                      {
                          Player p = Bukkit.getPlayer(player);
                          if(p == null)
                          {
                   
                      continue;
                  }  p.setExp((float) (p.getExp() + 0.15));
                      }
              }
             
          } 
      }, 0L, 15L);
     
      }
 
  public void onDisable() {
 
  }
 
  public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args){
      if(label.equals("timer"))
      {
          xpToPlayers.add(sender);
          addLevels = !addLevels;
          sender.sendMessage(ChatColor.DARK_BLUE + "Pomiar czasu " + ChatColor.RED +(addLevels ? "uruchomiony" : "zatrzymany."));
      }
      return false;
  }
  }
 

 

The toggle of players:

Code:java

// If the player is in the list
    if(xpToPlayers.contains(player.getName()))
    {
        // Remove him/her
        xpToPlayers.remove(player.getName());
    }
    // Else
    else
    {
        // Add him/her
        xpToPlayers.add(player.getName());
    }

 

It does not work. If I typed, / timer to measure the time I will, if you'll write when I have uruchominony timer, the timer will stop me this, and you do not begin to measure time.