Here's the log

at first I thought this was an issue with gradle, so I downgrade, but that didn't do anything, then I thought it was with loom so I downgraded that but same result; I realized I was using JDK 16 so I switch to 8 and same result.

already posted this on the discord, but why not here too.

This is not an issue from his side. I believe in newer versions of Fabric API 1.16.5 the abstract method IdentifiableResourceReloadListener#getFabricDependencies(). However as of now GeckoLib does not override that method which subsequently causes a LinkageError (AbstractMethodError).

EDIT: A solution would be to implement the unimplemented method getFabricDependencies() without annotating it with @ Override.

Nevermind

Yeah @Conclure I am testing on the newest and same version of Fabric API and loader as him and it's loading just fine

Although the issue persists. I think I found why.

	public static void initialize() {
		if (!hasInitialized) {
			ResourceManagerHelper.get(ResourceType.CLIENT_RESOURCES)
					.registerReloadListener(new IdentifiableResourceReloadListener() {
						@Override
						public Identifier getFabricId() {
							return new Identifier(GeckoLib.ModID, "models");
						}

						@Override
						public CompletableFuture<Void> reload(Synchronizer synchronizer, ResourceManager manager,
								Profiler prepareProfiler, Profiler applyProfiler, Executor prepareExecutor,
								Executor applyExecutor) {
							return GeckoLibCache.getInstance().reload(synchronizer, manager, prepareProfiler,
									applyProfiler, prepareExecutor, applyExecutor);
						}
					});
		}
		hasInitialized = true;
	}

The problem occurs here. GeckoLibCache#reload takes a ResourceReloadListener.Synchronizer instance whilst the unimplemented method specifies a ResourceReload.Synchronizer.

Needless to say I am uncertain whether I use the wrong version or if it's you.

EDIT:

This the versions I used:
minecraft_version=1.16.5
yarn_mappings=1.16.5+build.10
loader_version=0.11.6
fabric_version=0.36.0+1.16

Thanks Fabric FabricMC/yarn#2131 love your breaking changes, truly learning from Forge I see. Revert back to at least '0.29.4+1.16' for your ide, as shown the production version doesn't care so until I can fix my java issues thanks to Java 16, just do this for now.

It's on your end somewhere 🤷🏻 it's loading just fine here

Thanks Fabric FabricMC/yarn#2131 love your breaking changes, truly learning from Forge I see. Revert back to at least '0.29.4+1.16' for your ide, as shown the production version doesn't care so until I can fix my java issues thanks to Java 16, just do this for now.

I would like to say that you should rather revert back to yarn mappings version 1.16.5+build.3 to make it work. If you wanna use GeckoLib as of now @LonelyMusicDisc.