DavidM

Using hacks on servers is not wise and will result in a ban.

Post the new log with Java 8 or 10.

You don't. JavaFX is not involved in Minecraft at all.

It means you need to make your port public so your friends can access it. Read the manual of your router to learn how to port forward with your specific router.

Use less mods.

Personally, I would say yes. i.e. All the custom name part are completely not necessary, and the getField/setField with an id is pointless. use normal getters and setters instead.

It seems like you are following HarryTalks’ tutorials. Stop. His tutorials are terrible as they use outdated code and promote bad practices.

DartCraftReloaded is badly made and is broken. Remove the mod and report the crash to the author.

Try without texture pack. If this still occurs, post your logs according to the EAQ.

The stacktrace in the log indicates so.

If you are indeed downloading from the official site, there will not be such problem. Are you sure you are downloading from the official site? Are you sure you selected the right version (1.14.2) to download?

Just run the jar...

Unless you've changed your previous code, since "stack == new ItemStack(Block blockIn, int amount, int meta)" will never be true. Instead of direct comparison, it would be better to check the meta of the already existing ItemStack.

You could create an EventSubscriber for RenderGameOverlayEvent.Post and do your render there. You might want to look at how this is achieved in Botania.

This "if" check is pointless (the check for non-empty armor part) since you've wrote another "if" checking if the armor is your armor.