NullPointerException error

Hi community,

In the log file I very frequently get messages similar to the below example. Just the 4 lines every time, nothing more.
There is not enough info in it for me to determine what device this could possibly be coming from.
Are there any other possible ways anyone is aware of that could assist me working out what device is sending the message.

2024-02-08 00:36:12  INFO: [T367bde45] connected
2024-02-08 00:41:12  INFO: [T367bde45] timed out
2024-02-08 00:41:12  INFO: [T367bde45] disconnected
2024-02-08 00:41:12  INFO: [T367bde45] error - NullPointerException

Enable full stack traces.

Thanks Anton,
Now getting the below error. It is on customized code so the issue would be on my end.
Any idea which file I need to look at based on the error?

2024-02-09 10:22:00  INFO: [T9bfc28ef] connected
2024-02-09 10:22:00  INFO: [T9bfc28ef] disconnected
2024-02-09 10:22:00  INFO: [T9bfc28ef] error - 
java.lang.NullPointerException
    at java.base/java.util.concurrent.ConcurrentHashMap.replaceNode(ConcurrentHashMap.java:1111)
    at java.base/java.util.concurrent.ConcurrentHashMap.remove(ConcurrentHashMap.java:1102)
    at org.traccar.session.ConnectionManager.deviceDisconnected(ConnectionManager.java:191)
    at org.traccar.MainEventHandler.channelInactive(MainEventHandler.java:168)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:305)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
    at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:411)
    at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:376)
    at org.traccar.WrapperInboundHandler.channelInactive(WrapperInboundHandler.java:50)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:305)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
    at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81)
    at org.traccar.handler.OpenChannelHandler.channelInactive(OpenChannelHandler.java:38)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:303)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
    at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81)
    at io.netty.handler.timeout.IdleStateHandler.channelInactive(IdleStateHandler.java:277)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:303)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:274)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1405)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:301)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:281)
    at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:901)
    at io.netty.channel.AbstractChannel$AbstractUnsafe$7.run(AbstractChannel.java:813)
    at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
    at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:566)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:829)

You should be able to safely ignore this error.