larsgerrits

It's a VM argument, you append it to the java -jar ... line in your run script.

Learn Java. Learn Java. Learn Java. Learn Java.

And now you've just give him the code which he can copy-paste without learning anything from it.

Don't use a 20 minute video to setup your IDE. This is all you need to setup your IDE: https://mcforge.readthedocs.io/en/latest/gettingstarted/

Mojang doesn't write Minecraft with mod support in mind. That means that the code can change (a lot) between versions. Mods use that code to add new features. If the methods they use get removed between versions, that mod doesn't work on a newer version of Minecraft because it can't find that code anymore.

https://github.com/ichttt/MCLang2Json

You give it a different model. You can start by looking at the anvil.json files (the blockstate and model files).

Make Block#isOpaqueCube return false.

And with "from a user perspective" I meant: what should the user to do run this action? For example: the user presses a key or clicks a button in a GUI.

Your question (rephrased) was "how to add another project to an Eclipse workspace", right? That's exactly what I answered with.

That's because your using client-side only code. What is "exchange of packets"? From a user perspective, when do you want this to happen in the inventory?

They'll tackle this in the 1.14 update.

I understand. Google can be hard to use. Luckily, there's a website which has a nice animation to show you how to do it in the future: http://bfy.tw/K8xm

This is why the last few updates have been so big code-wise. They're trying to do make updating easier between versions by remaking their old systems.

I don't know if you're coding your mod that way or that your obfuscating it (for us), but please, don't! It makes it practically impossible for us to help you. What is MDL? What is a.b.c.MDL.Category.C?