I am getting a NoClassDefFoundError exception I don't know Why because my class is imported and there are no errors in the compiler but when I run the plugin the error is. I even checked if the .class file exists in the .jar file and it existed so I don't know what the problem is here is the exception I got:
[22:45:24] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'sb' in plugin YTScoreboard v2.6.3
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:149) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at org.bukkit.craftbukkit.v1_16_R3.CraftServer.dispatchCommand(CraftServer.java:761) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PlayerConnection.handleCommand(PlayerConnection.java:1936) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PlayerConnection.c(PlayerConnection.java:1779) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PlayerConnection.a(PlayerConnection.java:1732) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:49) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:1) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.PlayerConnectionUtils.lambda$0(PlayerConnectionUtils.java:28) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.TickTask.run(SourceFile:18) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeTask(SourceFile:144) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeNext(SourceFile:118) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.bb(MinecraftServer.java:1061) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.executeNext(MinecraftServer.java:1054) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeAll(SourceFile:103) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.sleepForTick(MinecraftServer.java:1037) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:970) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$0(MinecraftServer.java:273) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
at java.lang.Thread.run(Thread.java:831) [?:?]
Caused by: java.lang.NoClassDefFoundError: Could not initialize class pl.Werokowy.ytscoreboard.ScoreboadAPI
at pl.Werokowy.ytscoreboard.SBCmd.onCommand(SBCmd.java:57) ~[?:?]
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[1.16.jar:3096a-Spigot-9fb885e-af1a232]
... 19 more
The code is very simple so I rather not need to show it: ScoreboardAPI.updateScoreboard()