Spigot-API | OUTDATED - SEE https | GraphQL library

I want to write a plugin that can authenticate users by checking nosql database, but I bump into error when I try to run it in my server. I import the mongo driver using gradle but get NoClassDefFoundError. Here is the error code:

I'm new to Java and Spigot-API. I want to do a BlockBreakEvent which detects if a GOLD_ORE block got destroyed by a player. If so, it should replace that GOLD_ORE block with a STONE block. However it doesn't work and instead of replacing the block it drops the item which is a cobblestone of course.

My code:

I have multiple maven project. To change where the compiled jar is exported, I'm using maven-jar-plugin plugin like that :

I am trying to build a plugin for a Minecraft Spigot server that ultimately I would like to be able to communicate over serial with things connected to my PC (server is running locally on the PC as well).

I have been able to build and run the plugin and manipulate player/blocks in the game so I know the build process for my base plugin is working. My trouble started when I began trying to include an extra dependency: jSerialComm

I added the dependency entry in my pom.xml file:

I'm using the gradle shadow plugin in my java project.

I think I trying to solve this problem for any ways such as: CLASSPATH is wrong, Remove cache file , Restart.. etc...

BUT One interesting issues: I got fixed when I trying to add Libraries' New Java(such as spigot-1.17.1.jar) and Edit Modules Dependencies(Scope section) Normal Provided(Maven: org.spigotmc:spigot-api:1.17.1-R0.1-SNAPSHOT) -> Compile

Then this got fixed BUT I DON'T KNOW WHY THIS WORKING TO ME

EXPLAIN:

First of all, When I click(application menu) and press RUN button then I got this msg:

Error: Could not find or load main class me.kennytool.betaplugin.BetaPluginHandler.

Caused by: java.lang.NoClassDefFoundError: org/bukkit/event/Listener

IntelliJ displays these warning messages at Modules

enter image description here " Module xx is imported From Maven. Any changes made in its configuration might be lost after reimporting." (Note, this happens only when I press the Apply button on the Module)

I want to know what this means in detail and the solution...

For information Here:

Is there anyway to create an armorstand that is invisible to players and can float in air? I'm trying to make something like a boomerang that can be thrown but that requires an armorstand to show the boomerang itself. For example: Video. I use spigot-api-1.16.5-R0.1-20210220.225230-24 as my api.

With the Spigot-API, in Minecraft, I want to check if the Player is holding a specific Item in his hand. Can I somehow get the Item as comparative value from an Enum? I want to do that because I have some special Items with custom meta data and I want to have them in a enumeration list. Is this an eligible way? I tried something with a constructor in the enum but also I am too inexperienced in enums. -Or what would be a good way to store the items?

I just want to get the Item by doing: Items.NAME;

Would this be a solution?