Plugin not working

Hello, im new to programming in java and i just made a GUI plugin but when i type /changeteam in game nothing happens. Can someone please help me? Plugin is not showing any errors in console.

CODE:

Code:

package me.MaxBans.Minihra;

import java.util.ArrayList;
import java.util.List;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Color;
import org.bukkit.Material;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.inventory.meta.LeatherArmorMeta;
import org.bukkit.plugin.java.JavaPlugin;


import com.mojang.brigadier.Command;

import io.netty.buffer.ByteBuf;

import io.netty.handler.codec.http2.Http2Stream;


public class Main extends JavaPlugin implements Listener {
public Inventory inv;
    @Override
    public void onEnable()
    {
        this.getServer().getPluginManager().registerEvents((org.bukkit.event.Listener) this, this);
        createInv();
      
    }
  
    public void onDisable()
    {
      
      
    }
  
    public  boolean onCommand(CommandSender sender, Command cmd, String label, String[] args)
    {
        if(label.equalsIgnoreCase("changeteam")) {
            if(!(sender instanceof Player))
            {
                sender.sendMessage(ChatColor.RED + "You cannot do this!");
                return true;
            }
          
            Player player = (Player) sender;
            //open the GUI
            player.openInventory(inv);
            return true;
          
        }
        return false;
    }
  
    @EventHandler()
    public void onClick(InventoryClickEvent event) {
      
        if(!event.getInventory().equals(inv))
            return;
      
        if(event.getCurrentItem() == null) return;
        if(event.getCurrentItem().getItemMeta() == null) return;
        if(event.getCurrentItem().getItemMeta().getDisplayName() == null) return;
      
        event.setCancelled(true);
        Player player = (Player) event.getWhoClicked();
        if(event.getSlot() == 0) {
        //BLUE TEAM
            ItemStack[] armor = player.getEquipment().getArmorContents();
            armor = changeColor(armor, Color.BLUE);
            player.getEquipment().setArmorContents(armor);
            player.sendMessage(ChatColor.GOLD + "You changed your team!");
        }
      
        if(event.getSlot() == 1) {
            //RED TEAM
                ItemStack[] armor = player.getEquipment().getArmorContents();
                armor = changeColor(armor, Color.RED);
                player.getEquipment().setArmorContents(armor);
                player.sendMessage(ChatColor.GOLD + "You changed your team!");
            }
      
      
        if(event.getSlot() == 2) {
            //YELLOW TEAM
                ItemStack[] armor = player.getEquipment().getArmorContents();
                armor = changeColor(armor, Color.YELLOW);
                player.getEquipment().setArmorContents(armor);
                player.sendMessage(ChatColor.GOLD + "You changed your team!");
            }
      
      
        if(event.getSlot() == 3) {
            //GREEN TEAM
                ItemStack[] armor = player.getEquipment().getArmorContents();
                armor = changeColor(armor, Color.GREEN);
                player.getEquipment().setArmorContents(armor);
                player.sendMessage(ChatColor.GOLD + "You changed your team!");
            }
      
        //CLOSE
        if(event.getSlot() == 8) {
            player.closeInventory();
            }
      
        return;
    }
  
    public ItemStack[] changeColor(ItemStack [] a, Color color)
    {
        for(ItemStack item : a)
        {
            try {
                if(item.getType() == Material.LEATHER_BOOTS || item.getType() == Material.LEATHER_CHESTPLATE || item.getType() == Material.LEATHER_LEGGINGS || item.getType() == Material.LEATHER_HELMET) {
                    LeatherArmorMeta meta = (LeatherArmorMeta) item.getItemMeta();
                    meta.setColor(color);
                    item.setItemMeta(meta);
              
              
            }
              
            } catch (Exception e) {
                //do nothing
              
              
            }
          
          
        }
      
        return a;
    }
 
    public void createInv() {
    inv =  Bukkit.createInventory(null, 9, ChatColor.GRAY + "Select Team");
    ItemStack item = new ItemStack(Material.BLUE_CONCRETE);
    ItemMeta meta = item.getItemMeta();
  
    //BLUE TEAM
    meta.setDisplayName(ChatColor.DARK_BLUE + "BLUE TEAM");
    List<String> lore = new ArrayList<String>();
    lore.add(ChatColor.GRAY + "Click to join team!");
    meta.setLore(lore);
    item.setItemMeta(meta);
    inv.setItem(0, item);
  
    //RED TEAM
    item.setType(Material.RED_CONCRETE);
    meta.setDisplayName(ChatColor.DARK_RED + "RED TEAM");
    item.setItemMeta(meta);
    inv.setItem(1, item);
  
  
    //YELLOW TEAM
    item.setType(Material.YELLOW_CONCRETE);
    meta.setDisplayName(ChatColor.DARK_RED + "YELLOW TEAM");
    item.setItemMeta(meta);
    inv.setItem(2, item);
      
      
    //GREEN TEAM
    item.setType(Material.GREEN_CONCRETE);
    meta.setDisplayName(ChatColor.DARK_RED + "GREEN TEAM");
    item.setItemMeta(meta);
    inv.setItem(3, item);
  
    //close button
    item.setType(Material.BARRIER);
    meta.setDisplayName(ChatColor.RED + "Close menu");
    lore.clear();
    meta.setLore(lore);
    item.setItemMeta(meta);
    inv.setItem(8, item);

      
    }

    public void onGoAwayReceived(int arg0, long arg1, ByteBuf arg2) {
      
    }

    public void onGoAwaySent(int arg0, long arg1, ByteBuf arg2) {
        // TODO Auto-generated method stub
      
    }

    public void onStreamActive(Http2Stream arg0) {
      
    }

    public void onStreamAdded(Http2Stream arg0) {
      
    }

    public void onStreamClosed(Http2Stream arg0) {
        // TODO Auto-generated method stub
      
    }

    public void onStreamHalfClosed(Http2Stream arg0) {
        // TODO Auto-generated method stub
      
    }

    public void onStreamRemoved(Http2Stream arg0) {
        // TODO Auto-generated method stub
      
    }
}

 

I dont know, how do i do that?

Oh wait, i think i fixed it i had a bad import there

EDIT by Moderator: merged posts, please use the edit button instead of double posting.