I have a packet, designed to update both an item's inventory and the player's inventory by switching an item between both of them. Every time it's received (it's on the receiving end as far as I can tell), the world closes giving me a screen saying "A fatal error has occurred, this connection is terminated". I cannot for the life of me find out why this is happening (although I'm certain it's going to be something blatantly obvious), and I'm sure I've double-checked every line of code. The crash log suggests a problem initialising the packet class after code inside of it has been run. If anybody can find out what's going on I'd be very grateful.

 

Here is the packet class:

 

 

public class InventoryUpdate implements IMessage
{
private int sectorMouseIsIn;

public InventoryUpdate(int sectorMouseIsIn, BagInventory bagInventory)
{
	this.sectorMouseIsIn = sectorMouseIsIn;

	/*
	 * for(int i = 0; i < bagInventory.SIZE; i++) { System.out.println(bagInventory.getStackInSlot(i)); }
	 */
	HotbarBag.logger.info("Constructor");
}

@Override
public void fromBytes(ByteBuf buf)
{
	HotbarBag.logger.info("fromBytes1");
	this.sectorMouseIsIn = ByteBufUtils.readVarInt(buf, 1);
	HotbarBag.logger.info("fromBytes2");
}

@Override
public void toBytes(ByteBuf buf)
{
	ByteBufUtils.writeVarInt(buf, this.sectorMouseIsIn, 1);
	HotbarBag.logger.info("toBytes");
}

public static class Handle implements IMessageHandler<InventoryUpdate, IMessage>
{
	@Override
	public IMessage onMessage(InventoryUpdate message, MessageContext ctx)
	{
		HotbarBag.logger.info("Handle");
		InventoryHelper.updateInventory(new BagInventory(ctx.getServerHandler().playerEntity.getHeldItem()), ctx.getServerHandler().playerEntity, message.sectorMouseIsIn);
		HotbarBag.logger.info("Inventories successfully updated");
		return null;
	}
}
}

 

 

 

And where it is called from:

 

 

@SubscribeEvent
public void onClientTick(TickEvent.ClientTickEvent event)
{
	if (event.phase == TickEvent.Phase.START)
	{
		if (this.pressedLastTick && !HotbarBag.bagHUD.getIsKeyPressed())
		{
			Minecraft.getMinecraft().setIngameFocus();
			HotbarBag.networkWrapper.sendToServer(new InventoryUpdate(this.renderOverlayEventHandler.getMouseSector(), this.renderOverlayEventHandler.getInventory())); //Create packet
			System.out.println("Close");
		}
		this.pressedLastTick = HotbarBag.bagHUD.getIsKeyPressed();
	}
}

 

 

 

And the main class, where it's registered:

 

 

this.networkWrapper = NetworkRegistry.INSTANCE.newSimpleChannel("hotbarBag_inv");
this.networkWrapper.registerMessage(Handle.class, InventoryUpdate.class, 0, Side.SERVER);

 

 

 

 

And here is the crash log:

 

 

[11:34:41] [server thread/ERROR] [FML]: FMLIndexedMessageCodec exception caught
io.netty.handler.codec.DecoderException: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:99) ~[MessageToMessageDecoder.class:?]
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) ~[MessageToMessageCodec.class:?]
at io.netty.channel.DefaultChannelHandlerContext.invokeChannelRead(DefaultChannelHandlerContext.java:337) [DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelHandlerContext.fireChannelRead(DefaultChannelHandlerContext.java:323) [DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:785) [DefaultChannelPipeline.class:?]
at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:169) [EmbeddedChannel.class:?]
at cpw.mods.fml.common.network.internal.FMLProxyPacket.processPacket(FMLProxyPacket.java:86) [FMLProxyPacket.class:?]
at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:241) [NetworkManager.class:?]
at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:182) [NetworkSystem.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:726) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752) [MinecraftServer$2.class:?]
Caused by: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at java.lang.Class.newInstance(Unknown Source) ~[?:1.7.0_80]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:75) ~[FMLIndexedMessageToMessageCodec.class:?]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:17) ~[FMLIndexedMessageToMessageCodec.class:?]
at io.netty.handler.codec.MessageToMessageCodec$2.decode(MessageToMessageCodec.java:81) ~[MessageToMessageCodec$2.class:?]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:89) ~[MessageToMessageDecoder.class:?]
... 13 more
[11:34:41] [server thread/ERROR] [FML]: SimpleChannelHandlerWrapper exception
io.netty.handler.codec.DecoderException: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:99) ~[MessageToMessageDecoder.class:?]
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) ~[MessageToMessageCodec.class:?]
at io.netty.channel.DefaultChannelHandlerContext.invokeChannelRead(DefaultChannelHandlerContext.java:337) [DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelHandlerContext.fireChannelRead(DefaultChannelHandlerContext.java:323) [DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:785) [DefaultChannelPipeline.class:?]
at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:169) [EmbeddedChannel.class:?]
at cpw.mods.fml.common.network.internal.FMLProxyPacket.processPacket(FMLProxyPacket.java:86) [FMLProxyPacket.class:?]
at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:241) [NetworkManager.class:?]
at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:182) [NetworkSystem.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:726) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752) [MinecraftServer$2.class:?]
Caused by: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at java.lang.Class.newInstance(Unknown Source) ~[?:1.7.0_80]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:75) ~[FMLIndexedMessageToMessageCodec.class:?]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:17) ~[FMLIndexedMessageToMessageCodec.class:?]
at io.netty.handler.codec.MessageToMessageCodec$2.decode(MessageToMessageCodec.java:81) ~[MessageToMessageCodec$2.class:?]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:89) ~[MessageToMessageDecoder.class:?]
... 13 more
[11:34:41] [server thread/ERROR] [FML]: There was a critical exception handling a packet on channel hotbarBag_inv
io.netty.handler.codec.DecoderException: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:99) ~[MessageToMessageDecoder.class:?]
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) ~[MessageToMessageCodec.class:?]
at io.netty.channel.DefaultChannelHandlerContext.invokeChannelRead(DefaultChannelHandlerContext.java:337) ~[DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelHandlerContext.fireChannelRead(DefaultChannelHandlerContext.java:323) ~[DefaultChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:785) ~[DefaultChannelPipeline.class:?]
at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:169) ~[EmbeddedChannel.class:?]
at cpw.mods.fml.common.network.internal.FMLProxyPacket.processPacket(FMLProxyPacket.java:86) [FMLProxyPacket.class:?]
at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:241) [NetworkManager.class:?]
at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:182) [NetworkSystem.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:726) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752) [MinecraftServer$2.class:?]
Caused by: java.lang.InstantiationException: roboguy99.hotbarBag.network.packet.InventoryUpdate
at java.lang.Class.newInstance(Unknown Source) ~[?:1.7.0_80]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:75) ~[FMLIndexedMessageToMessageCodec.class:?]
at cpw.mods.fml.common.network.FMLIndexedMessageToMessageCodec.decode(FMLIndexedMessageToMessageCodec.java:17) ~[FMLIndexedMessageToMessageCodec.class:?]
at io.netty.handler.codec.MessageToMessageCodec$2.decode(MessageToMessageCodec.java:81) ~[MessageToMessageCodec$2.class:?]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:89) ~[MessageToMessageDecoder.class:?]
... 13 more

 

 

IMessage classes must have a constructor without arguments.

 

Ah! That did it, thanks.