Well, there are two logs: "minecraft:log" and "minecraft:log2"
One of them is oak, spruce, jungle, and birch, the other is acacia and dark oak. You're trying to set log2 to oak, which is not an allowed variant.
What do you want to use these resources for?
Its completely possible to autogenerate your resources using gradle it in your development workspace, but you would never want to do it in production
Also post your code.
Heres an example of registration that works perfectly https://github.com/Cadiboo/Example-Mod/blob/d828cd29685f7732cac6a2a8cd0f5cbfee5d6e88/src/main/java/io/github/cadiboo/examplemod/ModEventSubscriber.java#L106-L118
No. That is the registry name of the entry. You need to bind a Renderer for your entity if you want it to be rendered.
The rendering lookup is class based, so because your entity extends EntityArrow, the normal arrow renderer is rendering your entity. Example registering entity renderer https://gist.github.com/Cadiboo/3f5cdb785affc069af2fa5fdf2d70358#file-clienteventsubscriber-java-L69
Yeah, I had this issue too, and it took a few minutes to find the answer.
Short version: override drawScreen in your GuiContainer and put a this.renderHoveredToolTip(mouseX, mouseY); in there
I tried it in the background and foreground render methods, but neither one worked quite right. I think it was Draco18s that posted the above fix for someone once upon a time that I found while googling.