Spigot jar error?

at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:814) [Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.ServerConnection.c(ServerConnection.java:148) [Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.NetworkManager.a(NetworkManager.java:231) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.LoginListener.c(LoginListener.java:54) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.LoginListener.b(LoginListener.java:144) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.PlayerList.a(PlayerList.java:174) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.EntityPlayer.syncInventory(EntityPlayer.java:174) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO at net.minecraft.server.v1_8_R3.Container.addSlotListener(Container.java:56) ~[Spigot.jar:git-Spigot-21fe707-e1ebe52] 03.05 07:57:18 [Server] INFO java.lang.IllegalArgumentException: Listener already listening






Can anyone help me to fix it ? is it the error of the spigot?

 

i tried turning it from 1.8.8 to 1.8 still experience it

 

i figured it out
but i haven't fixed the problerm it should be the op thing

 

Yep fixed it, it is the OP list json thing. idk why is it corrupted

 

No now it is not fixed. I can tell, it is the op json's problem. For now, i can join without op. but once i op myself i cannot join

 

it is useless. If i op myself later, it crashes again