Thanks for the nice port to 1.14, but still it has a severe problem. A lot of errors such as "unknown materials" due to new CraftBukkit (this plugin uses CraftBukkit) API. As a Java-familiar developer, I want to thank you for leaving the source code, so I can help you. I just updated all libraries (to 1.14 if it was possible) and fixed the errors, then rebuilt the plugin so now it works perfectly without any errors spotted anymore. If you leave any contacts I'll be able to send you the fixed version for 1.14 I did. Thanks again, best regards.