ForgeNetworkTestMod.java

package net.minecraftforge.fml.test;
import io.netty.buffer.Unpooled;
import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.network.PacketBuffer;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.Mod.EventHandler;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import net.minecraftforge.fml.common.gameevent.PlayerEvent.PlayerLoggedInEvent;
import net.minecraftforge.fml.common.network.FMLEventChannel;
import net.minecraftforge.fml.common.network.NetworkRegistry;
import net.minecraftforge.fml.common.network.internal.FMLProxyPacket;
import net.minecraftforge.fml.relauncher.Side;

@Mod(modid = ForgeNetworkTestMod.MOD_ID, name = ForgeNetworkTestMod.MOD_ID, acceptableRemoteVersions = "*")
public class ForgeNetworkTestMod
{
    public static final String MOD_ID = "forgenetworktest";
    private FMLEventChannel channel;

    @EventHandler
    public void onPreInit(FMLPreInitializationEvent e)
    {
        if (e.getSide() == Side.SERVER)
        {
            MinecraftForge.EVENT_BUS.register(this);
            channel = NetworkRegistry.INSTANCE.newEventDrivenChannel(MOD_ID);
            channel.register(this);
        }
    }

    @SubscribeEvent
    public void onPlayerLogin(PlayerLoggedInEvent e)
    {
        if (channel == null)
            return;
        PacketBuffer buffer = new PacketBuffer(Unpooled.buffer());
        buffer.writeByte(0);
        channel.sendTo(new FMLProxyPacket(buffer, MOD_ID), (EntityPlayerMP)e.player); // disconnects vanilla clients in 1.11
    }
}