ForgeGradle

It doesn't exist anymore, you have to make the methods manually, it looks a bit like this: public class MyMessage { int value; public MyMessage(int value) { this.value = value; } public static void encode(MyMessage msg, PacketBuffer buffer) { buffer.writeInt(msg.value); } public static MyMessage decode(PacketBuffer buffer) { return new MyMessage(buffer.readInt()); //Remember to read in the same oreder you wrote! } public static void handle(MyMessage msg, Supplier<NetworkEvent.Context> ctx) { if (ctx.get().getDirection() == NetworkDirection.PLAY_TO_SERVER) { //Checks if the packet's direction is to the server ctx.get().enqueueWork(() -> { //Your code goes here }); } ctx.get().setPacketHandled(true); } } I'm 99% sure that's correct, kinda freestyled it though. To send it use SimpleChannel#sendToServer, don't forget to register it with SimpleChannel#registerMessage, and don't worry if you don't understand it right away, it took me a while to fully understand packets in 1.15.

https://mcforge.readthedocs.io/en/latest/networking/simpleimpl/

In your container you create a new ItemStackHandler, which is completely separate from your TE and thus will lose all it's data after closing the container.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

I changed TileEntity and Container class  but It still does nothing TE: package com.budrunbun.lavalamp.tileEntities; import com.budrunbun.lavalamp.containers.CheeseGeneratorContainer; import net.minecraft.entity.player.PlayerEntity; import net.minecraft.entity.player.PlayerInventory; import net.minecraft.inventory.container.Container; import net.minecraft.inventory.container.INamedContainerProvider; import net.minecraft.nbt.CompoundNBT; import net.minecraft.tileentity.TileEntity; import net.minecraft.util.text.ITextComponent; import net.minecraft.util.text.TranslationTextComponent; import net.minecraftforge.items.ItemStackHandler; import javax.annotation.Nullable; public class CheeseGeneratorTE extends TileEntity implements INamedContainerProvider { private final ItemStackHandler handler = new ItemStackHandler(1) { @Override protected void onContentsChanged(int slot) { super.onContentsChanged(slot); markDirty(); } }; public CheeseGeneratorTE() { super(ModTileEntities.CHEESE_GENERATOR_TE); } @Override public void read(CompoundNBT compound) { handler.deserializeNBT(compound.getCompound("inv")); super.read(compound); } @Override public CompoundNBT write(CompoundNBT compound) { compound.put("inv",handler.serializeNBT()); return super.write(compound); } @Override public ITextComponent getDisplayName() { return new TranslationTextComponent("cheese_generator"); } @Nullable @Override public Container createMenu(int windowId, PlayerInventory playerInventory, PlayerEntity playerEntity) { return new CheeseGeneratorContainer(windowId, playerInventory); } } Container: package com.budrunbun.lavalamp.containers; import net.minecraft.entity.player.PlayerEntity; import net.minecraft.entity.player.PlayerInventory; import net.minecraft.inventory.IInventory; import net.minecraft.inventory.container.Container; import net.minecraft.inventory.container.Slot; import net.minecraft.item.ItemStack; import net.minecraftforge.common.util.LazyOptional; import net.minecraftforge.items.IItemHandler; import net.minecraftforge.items.ItemStackHandler; import net.minecraftforge.items.SlotItemHandler; import javax.annotation.Nonnull; public class CheeseGeneratorContainer extends Container { private final ItemStackHandler handler = new ItemStackHandler(1); public CheeseGeneratorContainer(int windowId, PlayerInventory playerInventory) { super(ModContainers.CHEESE_GENERATOR_CONTAINER, windowId); this.addSlot(new SlotItemHandler(handler, 0, 12 + 4 * 18, 8 + 2 * 18)); int leftCol = (184 - 162) / 2 + 1; for (int playerInvRow = 0; playerInvRow < 3; playerInvRow++) { for (int playerInvCol = 0; playerInvCol < 9; playerInvCol++) { this.addSlot(new Slot(playerInventory, playerInvCol + playerInvRow * 9 + 9, leftCol + playerInvCol * 18, 184 - (4 - playerInvRow) * 18 - 10)); } } for (int hotbarSlot = 0; hotbarSlot < 9; hotbarSlot++) { this.addSlot(new Slot(playerInventory, hotbarSlot, leftCol + hotbarSlot * 18, 184 - 24)); } } @Override public boolean canInteractWith(PlayerEntity playerIn) { return true; } }