#28 onPacketInAsync error

at de.Linus122.AdvancedOreGen.GUI.SignListener.processSign(SignListener.java:88) ~[AdvancedOreGen.jar:?]
at de.Linus122.AdvancedOreGen.GUI.SignListener.access$3(SignListener.java:87) ~[AdvancedOreGen.jar:?]
at de.Linus122.AdvancedOreGen.GUI.SignListener$1.onPacketInAsync(SignListener.java:60) ~[AdvancedOreGen.jar:?]
at de.Linus122.AdvancedOreGen.nms.TinyProtocol$PacketInterceptor.channelRead(TinyProtocol.java:499) [AdvancedOreGen.jar:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:168) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector$4.channelRead(NettyChannelInjector.java:280) [ProtocolLib.jar:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.handler.timeout.ReadTimeoutHandler.channelRead(ReadTimeoutHandler.java:150) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.epoll.EpollSocketChannel$EpollSocketUnsafe.epollInReady(EpollSocketChannel.java:722) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:326) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:264) [spigot.jar:git-Spigot-db6de12-18fbb24]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [spigot.jar:git-Spigot-db6de12-18fbb24]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_242]

Last night I had this error and crashed our server: [Netty Epoll Server IO #3/ERROR]: [AdvancedOreGen] Error in onPacketInAsync(). java.lang.NullPointerException at de.Linus122.AdvancedOreGen.GUI.SignListener.processSign(SignListener.java:88) ~[AdvancedOreGen.jar:?] at de.Linus122.AdvancedOreGen.GUI.SignListener.access$3(SignListener.java:87) ~[AdvancedOreGen.jar:?] at de.Linus122.AdvancedOreGen.GUI.SignListener$1.onPacketInAsync(SignListener.java:60) ~[AdvancedOreGen.jar:?] at de.Linus122.AdvancedOreGen.nms.TinyProtocol$PacketInterceptor.channelRead(TinyProtocol.java:499) [AdvancedOreGen.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:168) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector$4.channelRead(NettyChannelInjector.java:280) [ProtocolLib.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.handler.timeout.ReadTimeoutHandler.channelRead(ReadTimeoutHandler.java:150) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.epoll.EpollSocketChannel$EpollSocketUnsafe.epollInReady(EpollSocketChannel.java:722) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:326) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:264) [spigot.jar:git-Spigot-db6de12-18fbb24] at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [spigot.jar:git-Spigot-db6de12-18fbb24] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_242]