[SERVER][21:27:06 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'ggc' in plugin GuoGroupCommand v1.4.0
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[patched_1.12.2.jar:git-Paper-1620]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:152) ~[patched_1.12.2.jar:git-Paper-1620]
        at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:685) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.PlayerConnection.handleCommand(PlayerConnection.java:1492) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1297) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.PlayerConnectionUtils.la[SERVER]mbda$ensureMainThread$0(PlayerConnectionUtils.java:14) ~[patched_1.12.2.jar:git-Paper-1620]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_391]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_391]
        at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:850) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[patched_1.12.2.jar:git-Paper-1620]
        at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[patched_1.12.2.jar:git-Paper-1620]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_391]
Caused by: java.lang.InternalError: Malformed class name
        at java.lang.Class.getSimpleName(Unknown Source) ~[?:1.8.0_391]
        at java.lang.Class.isAn[SERVER]onymousClass(Unknown Source) ~[?:1.8.0_391]
        at co.aikar.timings.MinecraftTimings.lambda$getPluginTaskTimings$0(MinecraftTimings.java:68) ~[patched_1.12.2.jar:git-Paper-1620]
        at java.util.concurrent.ConcurrentMap.computeIfAbsent(Unknown Source) ~[?:1.8.0_391]
        at co.aikar.timings.MinecraftTimings.getPluginTaskTimings(MinecraftTimings.java:67) ~[patched_1.12.2.jar:git-Paper-1620]
        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.<init>(CraftTask.java:47) ~[patched_1.12.2.jar:git-Paper-1620]
        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.runTaskTimer(CraftScheduler.java:159) ~[patched_1.12.2.jar:git-Paper-1620]
        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.runTaskLater(CraftScheduler.java:133) ~[patched_1.12.2.jar:git-Paper-1620]
        at cn.gayaguoguo.guogroupcommand.a.IiiIIiIiii.iiiiiiIIii(z:8) ~[?:?]
        at cn.gayaguoguo.guogroupcommand.a.IiiIIiIiii.iiiiiiIIii(z:111) ~[?:?]
        at cn.gayaguoguo.guogroupcommand.GuoGroupCommand.onCommand(d:54) ~[?:?]
        at org.bukkit.command.Pl[SERVER]uginCommand.execute(PluginCommand.java:44) ~[patched_1.12.2.jar:git-Paper-1620]
        ... 15 more