Hi Julian,
I guess this is a simple timing issue and we shouldn't worry about it. Of course, throwing NPEs is a no-no and we should handle that. Having a more detailed look at the problem. I bet it's related to "channel" being reset in the AbstractPlcConnection.close method. We should investigate, if setting this to null is the right way to do it. If you have the time to investigate this, this would be super awesome. I hope I'll be able to push a larger commit today as I am adding a new security tool to the build and this is reporting some things I have to fix first. Chris Am 01.08.18, 17:07 schrieb "Julian Feinauer" <[email protected]>: Hi all, I finally organized an S7 to play around a bit more with Plc4J and observed the following exception that is always thrown when calling close on the S7PlcConnection: 17:04:54.438 [nioEventLoopGroup-2-1] WARN i.n.util.concurrent.DefaultPromise - An exception was thrown by org.apache.plc4x.java.s7.connection.S7PlcConnection$$Lambda$8/1293618474.operationComplete() java.lang.NullPointerException: null at org.apache.plc4x.java.s7.connection.S7PlcConnection.lambda$close$5(S7PlcConnection.java:188) at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:511) at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:485) at io.netty.util.concurrent.DefaultPromise.access$000(DefaultPromise.java:33) at io.netty.util.concurrent.DefaultPromise$1.run(DefaultPromise.java:435) at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463) at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:745) Is this due to some problems on my side or my S7 or is this a hint to a bug? Best Julian
