服务器后台一只乱码,时间长了会崩服，不知道是被人压测还是怎么，求大神救  乱码如下

1.04 21:35:13 [Server] INFO at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_75]

11.04 21:35:13 [Server] INFO at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_75]

11.04 21:35:13 [Server] INFO at sun.reflect.GeneratedMethodAccessor240.invoke(Unknown Source) ~[?:?]

11.04 21:35:13 [Server] INFO at Listener.PlayerEvent.onInventoryClick(PlayerEvent.java:59) ~[?:?]

11.04 21:35:13 [Server] INFO at java.lang.String.indexOf(Unknown Source) ~[?:1.7.0_75]

11.04 21:35:13 [Server] INFO at java.lang.String.indexOf(Unknown Source) ~[?:1.7.0_75]

11.04 21:35:13 [Server] INFO Caused by: java.lang.NullPointerException

11.04 21:35:13 [Server] INFO at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [spigot-1.7.2.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]

11.04 21:35:13 [Server] INFO at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:469) [spigot-1.7.2.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]

11.04 21:35:13 [Server] INFO at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:562) [spigot-1.7.2.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]

11.04 21:35:13 [Server] INFO at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:273) [spigot-1.7.2.jar:git-Spigot-1.7.2-R0.3-122-gb58e277]

求帮忙！