DaemonUmbra

The filenames of one or more of your mods suggests you got them from a repost site. Please read up on the StopModReposts project (link in my signature) for info on why this is a bad thing.

Try google?

1.6.5 is no longer supported on this forum due to its age. Please update to a modern version of Minecraft to receive support.

I'm not 100% sure, but it looks like the server is crashing when it attempts to load a chunk and ends up getting stuck behind multithread sync, if a member of the dev team could correct me if I'm wrong that would be great.

Oh right... derp. https://stackoverflow.com/questions/15826202/where-is-java-installed-on-mac-os-x

You were literally told that the links won't work, then proceeded to complain about the links not working. Regardless, you are obviously trying to run a version of Minecraft that we no longer support. Locked.

Sounds like you're missing a mod that the server requires.

User was banned for using a cracked launcher.

Ok, the crash log doesn't indicate the issue being memory, but right there your server and client are hogging 12G/16G, so make sure to not run anything else RAM hungry. What's your CPU?

What do you mean "activate the engine"? Please provide a screenshot.

How much are you giving your client?

Oh right, not going to get what I was looking for if it uses the wrong Java... erm. Assuming you installed the correct bitness of Java 8, it should be in C:\Program Files\Java\<java version>\bin\

How much RAM do you have in your machine? Remember you will need RAM for the server, RAM for your client, and RAM for everything else your computer is doing, as well as a CPU with enough grunt to run garbage collection on that memory.

What did I say that suggested Forge for 1.14.4 is buggy? I would suggest only getting mods from CurseForge, clear out your mods folder and get everything from there.

Server committed Seppuku because it was running too slow. What is this server running on?

... Really?

Ok that should be Oracle Java, could you run the command java -version and share the output, please?

Where did you get Java from? Oracle, OpenJDK, AdoptOpenJDK, Java.com?

Are you trying to run mods? If so you need to run a Forge server, not a vanilla server.

Please do not manually download libraries...

Why do you have a fabric installer in your mods folder? Why do you have folders in your mods folder? Where are you getting your mods? Optifine is not compatible with Forge yet.

Yes. Essentially what your current command does is tell your computer: "Find a program called 'java' and run it with these arguments" What I'm telling you to do instead tells your computer: "Here's the location of a program, run it with these arguments"

Split your reply into its own thread, in the future do not hijack other people's threads.

Not yet, the Optifine team is working on it

Having it does not mean it's what your PC is trying to use, replace java with the full path to the java binary/executable.