[Bug]: NullPointerException

[JordanFromChina]

What happened?

// connected a S1500 PLC and cache it
// create PlcReadRequest instance and cache it
//get PlcReadRequest from cache
//a loop call program below

PlcReadRequest readRequest = cachedRequest.get(...);
PlcReadResponse response = readRequest.execute()
  .get(OpcConfig.synchronized_millisecond * 30, TimeUnit.MILLISECONDS);

Thread.sleep(100);
PlcResponseCode code;
Object value;
for (String fieldName : response.getTagNames()) {
        try {
            code = response.getResponseCode(fieldName);
            if (code == PlcResponseCode.OK) {
                ....
            } else { 
              log.error("field: {} responseCode: {}", fieldName, code);
            }
    }
    catch (InterruptedException e) {
    	throw e;
    }
    catch (Exception e) {
        String msg = e.getMessage();
        log.error(fieldName , e);
}

the logback file logged errors below sometimes

[plc4x-tm-thread-1] i.n.c.e.EmbeddedChannel - More than one exception was raised. Will report only the first one and log others.
java.lang.NullPointerException: Cannot invoke "io.netty.channel.ChannelPromise.setUncancellable()" because "entry.promise" is null
at io.netty.channel.ChannelOutboundBuffer.addFlush(ChannelOutboundBuffer.java:150)
at io.netty.channel.AbstractChannel$AbstractUnsafe.flush(AbstractChannel.java:894)
at io.netty.channel.embedded.EmbeddedChannel$EmbeddedUnsafe$1.flush(EmbeddedChannel.java:894)
at io.netty.channel.DefaultChannelPipeline$HeadContext.flush(DefaultChannelPipeline.java:1372)
at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:921)
at io.netty.channel.AbstractChannelHandlerContext.invokeFlush(AbstractChannelHandlerContext.java:907)
at io.netty.channel.AbstractChannelHandlerContext.flush(AbstractChannelHandlerContext.java:893)
at io.netty.channel.ChannelDuplexHandler.flush(ChannelDuplexHandler.java:127)
at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:923)
at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:941)
at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:966)
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:934)
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:984)
at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1025)
at org.apache.plc4x.java.spi.Plc4xNettyWrapper$1.sendToWire(Plc4xNettyWrapper.java:100)
at org.apache.plc4x.java.spi.internal.DefaultSendRequestContext.handle(DefaultSendRequestContext.java:108)
at org.apache.plc4x.java.spi.internal.DefaultSendRequestContext.handle(DefaultSendRequestContext.java:1)
at org.apache.plc4x.java.s7.readwrite.protocol.S7ProtocolLogic.lambda$42(S7ProtocolLogic.java:1535)
at org.apache.plc4x.java.spi.transaction.RequestTransactionManager$TransactionOperation.run(RequestTransactionManager.java:225)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:840)

Version

v0.13.1

Programming Languages

• plc4c
• plc4go
• plc4j
• plc4net
• plc4py

Protocols

• AB-Ethernet
• ADS /AMS
• BACnet/IP
• C-Bus
• CANopen
• EtherNet/IP
• Firmata
• IEC-69870
• KNXnet/IP
• Modbus
• OPC-UA
• Profinet
• S7
• S7-light

[chrisdutz]

Please try using the "s7-light" driver instead. If you're using a S7-1500 you can't use the communication form the s7 supports in addition to the s7-light anyway.

I built that to avoid such hard to trace back issues.