Plugin Help Teleport Plugin Help

Hello, I've been making a plugin for a server recently but I was wondering how I get a message to appear in the chat if the player is offline? If you could merge it into the below code, it would be more than helpful

Code:java

package me.top2001.OreCloudTeleport;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;
 
public class Main extends JavaPlugin{
 
    public void onEnable() {
        getLogger().info("Plugin Enabled!");
    }
 
    public void onDisable() {
        getLogger().info("Plugin Disabled!");
    }
 
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
          if(sender instanceof Player) {
          final String prefix = ChatColor.GREEN + "Ore" + ChatColor.GRAY + "Cloud" + ChatColor.DARK_GREEN + " > ";
          Player player = (Player) sender;
          Location loc = player.getLocation();
          if(cmd.getName().equalsIgnoreCase("tp")) {
              if (args.length == 0) {
                  player.sendMessage(prefix + ChatColor.GREEN + "Please specify a player. (/tp <Player> {TargetPlayer})");
              }else if (args.length == 1) {
                  Player targetPlayer = player.getServer().getPlayerExact(args[0]);
                  Location targetPlayerLocation = targetPlayer.getLocation();
                  player.teleport(targetPlayerLocation);
                  player.sendMessage(prefix + ChatColor.GREEN + "Now teleporting...");
              }else if (args.length == 2) {
                  Player targetPlayer = player.getServer().getPlayerExact(args[0]);
                  Player targetPlayer1 = player.getServer().getPlayerExact(args[1]);
                  Location targetPlayer1Location = targetPlayer1.getLocation();
                  targetPlayer.teleport(targetPlayer1Location);
                  player.sendMessage(prefix + ChatColor.GREEN + "Now teleporting...");
              }
              Player targetPlayer = Bukkit.getServer().getPlayerExact(args[0]);
              if (targetPlayer == null) {
                  player.sendMessage(prefix + ChatColor.GREEN + "The player, " + ChatColor.DARK_GREEN + args[0] + ChatColor.GREEN + ", is currently not online.");
              }
              Player targetPlayer1 = Bukkit.getServer().getPlayerExact(args[1]);
              if (targetPlayer1 == null) {
                  player.sendMessage(prefix + ChatColor.GREEN + "The player, " + ChatColor.DARK_GREEN + args[1] + ChatColor.GREEN + ", is currently not online.");
              }
          }
          // Sets Spawn.
          if(cmd.getName().equalsIgnoreCase("setspawn")) {
              if(sender.hasPermission("orecloudteleport.setspawn")){
                  player.getWorld().setSpawnLocation(player.getLocation().getBlockX(), player.getLocation().getBlockY(), player.getLocation().getBlockZ());
                  player.sendMessage(prefix + ChatColor.GREEN + "Spawn location created.");
              }else{
                  player.sendMessage(prefix + ChatColor.RED + "Sorry, you don't have permission to perform this command.");
              }
          }
          // Teleport Player To Spawn.
          if (cmd.getName().equalsIgnoreCase("spawn")) {
              if(sender.hasPermission("orecloudteleport.spawn")){
                  player.teleport(player.getWorld().getSpawnLocation());
                  player.sendMessage(prefix + ChatColor.GREEN + "Now sending you to spawn...");
              }else{
                  player.sendMessage(prefix + ChatColor.RED + "Sorry, you don't have permission to perform this command.");
                  return true;
              }
          }
          }
        return false;
    }
}