Error...

Some time ago there was a problem after which all the new plugins that I want to write do not work.

The console will show the error:

[23:37:36] [Server thread/ERROR]: Could not load 'plugins/Complate.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.IllegalArgumentException: Plugin already initialized!
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:327) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:248) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.loadPlugins(CraftServer.java:305) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.reload(CraftServer.java:750) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.Bukkit.reload(Bukkit.java:525) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:27) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:648) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchServerCommand(CraftServer.java:634) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.DedicatedServer.aP(DedicatedServer.java:444) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:407) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.Thread.run(Thread.java:834) [?:?]
Caused by: java.lang.IllegalArgumentException: Plugin already initialized!
at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:183) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:60) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at ru.MrKoLoTeR.Main.<init>(Main.java:6) ~[?:?]
at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:?]
at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?]
at java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[?:?]
at java.lang.Class.newInstance(Class.java:584) ~[?:?]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:90) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
... 14 more
Caused by: java.lang.IllegalStateException: Initial initialization
at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:186) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:60) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at ru.MrKoLoTeR.Main.<init>(Main.java:6) ~[?:?]
at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:?]
at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?]
at java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[?:?]
at java.lang.Class.newInstance(Class.java:584) ~[?:?]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:90) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
... 14 more