Unhandeled Exception executing command error

I coded a plugin to set a players permission(s) but when I try to use the /permission command in the console, I get following error message:
[17:22:09 WARN]: Unexpected exception while parsing console command "permission iJustLeyxo owner" org.bukkit.command.CommandException: Unhandled exception executing command 'permission' in plugin NeonPlugin v1.0 at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.craftbukkit.v1_17_R1.CraftServer.dispatchCommand(CraftServer.java:869) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.craftbukkit.v1_17_R1.CraftServer.dispatchServerCommand(CraftServer.java:832) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.dedicated.DedicatedServer.handleConsoleInputs(DedicatedServer.java:529) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:491) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1480) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1279) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319) ~[patched_1.17.1.jar:git-Paper-353] at java.lang.Thread.run(Thread.java:831) ~[?:?] Caused by: java.lang.IllegalArgumentException: Plugin already initialized! at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:229) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:53) ~[patched_1.17.1.jar:git-Paper-353] at ijustleyxo.neonplugin.NeonPlugin.<init>(NeonPlugin.java:9) ~[NeonPlugin-1.0.jar:?] at ijustleyxo.neonplugin.commands.CustomPermissionsCommand.onCommand(CustomPermissionsCommand.java:112) ~[NeonPlugin-1.0.jar:?] at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[patched_1.17.1.jar:git-Paper-353] ... 9 more Caused by: java.lang.IllegalStateException: Initial initialization at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:232) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:53) ~[patched_1.17.1.jar:git-Paper-353] at ijustleyxo.neonplugin.NeonPlugin.<init>(NeonPlugin.java:9) ~[NeonPlugin-1.0.jar:?] at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?] at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:78) ~[?:?] at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?] at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?] at java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:128) ~[?:?] at jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:350) ~[?:?] at java.lang.Class.newInstance(Class.java:642) ~[?:?] at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:83) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:153) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:414) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:322) ~[patched_1.17.1.jar:git-Paper-353] at org.bukkit.craftbukkit.v1_17_R1.CraftServer.loadPlugins(CraftServer.java:419) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:287) ~[patched_1.17.1.jar:git-Paper-353] at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1217) ~[patched_1.17.1.jar:git-Paper-353] ... 2 more

I cannot figure out what’s wrong so it would be verry nice if sb could help me.