Bukkit

In reply to gabbilabbi14:

 I probably should just set up a form reply to this kind of issue.

OI requires Spigot internals. I highly recommend you run a Forge mod for things like this instead; OI does not have support for concepts like dynamic additional inventory slots (e.g. Baubles or whatever the modern equivalent is). These combo servers have also been notoriously unreliable because mods have a tendency to accomplish their goals in various inconsistent ways that result in missed cases for Bukkit events.

If you want to see this fixed, you can ask the Magma team to add a Commodore entry to rewrite the method to their renamed method when loading plugins.

In reply to gabbilabbi14:

 Not a clue, I don't interact with the Forge side of the Minecraft scene. I had a friend who used a mod that doubled as a player NBT editor for it, but I never used it myself. It's possible that he was just using a raw NBT editor to "view" items, but he definitely appeared to be able to make live edits including obtaining items from others' inventories in a similar fashion to how OpenInv works. There's also no guarantee that the mod still exists.

/edit: Got an answer back from him, apparently there's a baked in FTB utility for it these days. The particular mod he used to use for live NBT edits died in 1.7.10, so now he uses NBTExplorer if there's something he can't access via the FTB inventory opening functionality.

I will say that if your goal is to actively monitor player inventory activity, you are much better off using a logging plugin (or, ideally, mod if such a mod exists) to search for suspicious activity. Checking inventories manually is generally not a good way to identify cheating because there's no context for how an item was obtained.

In reply to fl1mm3r:

 Frankly, if you're new to servers, do yourself a favor and run a modern server. Trying to run a secure legacy server, particularly with so old and unpopular a version, is a nightmare. /e: I should clarify - 1.0.0 was not a divisive version for the community, it did not have a major reason for players to not update past it. As a result, no one maintains anything for it that I'm aware of.

Any rate, you're trying to run a server version from before CB used versioned packages. You'll need to locate the correct build from years and years ago in the files for whatever ancient CB build you're using. I'm assuming based on the error that either you downloaded the wrong file or your server's internals do not match the expected format for a CB 1.0.0 server. If you downloaded the wrong file and do not have a CB build number, it's trial and error to find the file that actually matches your server. If the issue is that you're running some third party server, you may need to build your own version of OI against it.

I do note that your stack trace indicates you're running Java 11+, so even if you do find the correct build you may still need to build your own version of OI to account for the reflection changes in Java 9. Alternately, run your ancient server on ancient Java, namely Java 8.

In reply to qqq:

 Please respond to the request for information in https://github.com/Jikoo/OpenInv/issues/137.

In reply to shinging__Gem:

 Use 4.2.0 for 1.19 or 4.2.2 for 1.19.1/1.19.3.

In reply to TiroTear:

 I believe 1.19.2 had identical mappings to either 1.19.1 or 1.19.3, so presumable also 4.2.2. If it's different it's in the same boat as 1.19.0 - Spigot did not release an internal version bump so I cannot support it easily. It would be supported with whichever version was compiled against it, except no one told me there were issues so I never made a release for it. If you're having problems on 1.19.2 you should update your server to 1.19.3.

In reply to RealRedstoneMiner:

 4.0.0, specifically the OpenInv-legacy additional file. Note that if you're using a Forge variant, you should look for a Forge mod instead. The server variants that claim to support Bukkit plugins using Minecraft internals are notoriously unreliable.

In reply to hestiasan:

 4.2.1 is for 1.19.1, not 1.19. Use 4.2.0.

Because you are now the second person to have this issue, the text in the changelog is now large and red.

In reply to Sully1464:

 You included a single line of a much larger error. Please post the full error via a paste site.

At a guess without any further info, you probably have installed a version for 1.19.1/1.19.2 on a 1.19 server. Please make sure you read the supported versions section carefully.