HashMap checking and rewriting coordinates

Hi, I need help with HashMap. When I click the left mouse button, the coordinates are taken, and then I have to check if these coordinates have already been taken, then overwrite, if not, they are added to the configuration, but I don’t understand how to check and overwrite the existing ones and save them. I apologize for the spelling. I am just Russian and do not know much English. And yes, I'm still a beginner)

code/

Code:

package PrizeParkour;
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.World;
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;
public class RigthClick implements Listener  {
  
    @EventHandler
    public void arrowstick(PlayerInteractEvent event) {
        Player p = event.getPlayer();
        if(event.getAction() == Action.LEFT_CLICK_BLOCK){
            if(p.getInventory().getItemInMainHand().getType().equals(Material.BLAZE_ROD) && p.getInventory().getItemInMainHand().getItemMeta().hasDisplayName()) {
                if(p.getInventory().getItemInMainHand().getItemMeta().getDisplayName().equals(ChatColor.translateAlternateColorCodes('&',"&6Wand"))) {
                    for(String line : PrizeParkour.Language.getStringList("messages.point")) {
                        p.sendMessage(ChatColor.translateAlternateColorCodes('&',line));
                    }
                    event.setCancelled(true);
                    Location location = event.getClickedBlock().getLocation();
                    String loc = location.getWorld().getName() + "," + location.getX() + "," + location.getY() + "," + location.getZ() + "," + location.getPitch() + "," + location.getYaw();
                    String[] array = {p.getDisplayName(),loc};
                    if(playerSearch(p.getDisplayName()))
                        PrizeParkour.selections.add(array);
                    else
                        PrizeParkour.selections.add(array);
                }
            }
        }
    }
    public static Location getDeserializedLocation(String s) {
        String [] split = s.split(";");
        return new Location(Bukkit.getWorld(split[0]), Double.parseDouble(split[1]), Double.parseDouble(split[2]), Double.parseDouble(split[3]), Float.parseFloat(split[4]), Float.parseFloat(split[5]));
    }
  
    public Boolean playerSearch(String player) {
        for(int i = 0; i < PrizeParkour.selections.length; i++) {
            if(PrizeParkour.selections[I][0].equals(player)) {
                return i;
            }
        }
        return 0;
    }
}[code][/I]