import xyz.refinedev.api.tablist.TablistHandler;
import xyz.refinedev.api.tablist.adapter.impl.ExampleAdapter;

import com.github.retrooper.packetevents.PacketEventsAPI;

public class ExamplePlugin extends JavaPlugin {

    private TablistHandler tablistHandler;
    private PacketEventsAPI<?> packetEvents;

    @Override
    public void onEnable() {
        //this.packetEvents.init();
        this.tablistHandler = new TablistHandler(plugin);
        this.tablistHandler.init(this.packetEvents, new TeamsPacketListener(this.packetEvents));
        this.tablistHandler.registerAdapter(new ExampleAdapter(tablist), 20L);
    }
}

import xyz.refinedev.api.tablist.adapter.TabAdapter;

public class TablistAdapter implements TabAdapter {

    /**
     * Get the tab header for a player.
     *
     * @param player the player
     * @return string
     */
    public String getHeader(Player player) { // String or you can use \n to use multiple lines
        return "Example";
    } 

    /**
     * Get the tab player for a player.
     *
     * @param player the player
     * @return string
     */
    public String getFooter(Player player) { // String or you can use \n to use multiple lines
        return "Example";
    }
    
    /**
     * Get the tab lines for a player.
     *
     * @param player the player
     * @return list of entries
     */
    public List<TabEntry> getLines(Player player) {  // Tab Entry contains the string, skin, slot and ping of the tablist slot
        List<TabEntry> entries = new ArrayList<>();

        List<Player> players = new ArrayList<>(Bukkit.getOnlinePlayers());
        
        for ( int i = 0; i < 80; i++ ) {
            final int x = i % 4;
            final int y = i / 4;

            if (players.size() <= i) continue;

            Player tabPlayer = players.get(i);
            if (tabPlayer == null) continue;

            entries.add(new TabEntry(x, y, tabPlayer.getDisplayName(), tabPlayer.spigot().getPing(), Skin.getPlayer(tabPlayer)));
        }

        return entries;
    }
}