Minecraft plugin is not recognized?

I created a Minecraft plugin that will later be used on a server, for which I tested the plugin on my local host, where it worked. Then I uploaded it to the Minecraft server via an FTP client and restarted it, but it wasn't there!

Both run on the Spigot version 1.8.8! And JDK14.0.1 under JRE 1.8

All other plugins from me don't work either! ONLY OLD

1. Please get used to writing plugins according to the Java standard and 2. Is not really recognizable on the picture. Did you register the events in the Main correctly? Is the plugin.yml correct? If your plugin runs on the localhost, but not on the other, I would set up the server from scratch.

I know that not everything is written according to the Java standard because it had to be done quickly. The whole thing is registered in the Main like this: Bukkit.getPluginManager (). RegisterEvents (new Join (), this);

Actually, the problem should not be entirely on the server, since the plugin (in a different version [only changed the message]) ran briefly on the server, but was gone after the next reload)