[network] NPE in PresenceDetection.enableDHCPListen() while disposing ThingHandler

[cweitkamp]

You will see this NPE whenever a hostname cannot be resolved to an IP address (e.g. if you configure an unknown hostname).

2018-04-17 21:05:10.229 [ERROR] [nal.common.AbstractInvocationHandler] - An error occurred while calling method 'ThingHandler.dispose()' on 'org.openhab.binding.network.handler.NetworkHandler@1bc4277': null
java.lang.NullPointerException: null
    at org.openhab.binding.network.internal.PresenceDetection.enableDHCPListen(PresenceDetection.java:524) [224:org.openhab.binding.network:2.3.0.201804141026]
    at org.openhab.binding.network.internal.PresenceDetection.stopAutomaticRefresh(PresenceDetection.java:500) [224:org.openhab.binding.network:2.3.0.201804141026]
    at org.openhab.binding.network.handler.NetworkHandler.dispose(NetworkHandler.java:143) [224:org.openhab.binding.network:2.3.0.201804141026]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:?]
    at org.eclipse.smarthome.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.java:153) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
    at org.eclipse.smarthome.core.internal.common.Invocation.call(Invocation.java:53) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
    at java.lang.Thread.run(Thread.java:748) [?:?]
2018-04-17 21:05:10.235 [ERROR] [ome.core.thing.internal.ThingManager] - Exception occurred while disposing handler of thing 'network:pingdevice:myphone': null
java.lang.NullPointerException: null
    at org.openhab.binding.network.internal.PresenceDetection.enableDHCPListen(PresenceDetection.java:524) [224:org.openhab.binding.network:2.3.0.201804141026]
    at org.openhab.binding.network.internal.PresenceDetection.stopAutomaticRefresh(PresenceDetection.java:500) [224:org.openhab.binding.network:2.3.0.201804141026]
    at org.openhab.binding.network.handler.NetworkHandler.dispose(NetworkHandler.java:143) [224:org.openhab.binding.network:2.3.0.201804141026]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:?]
    at org.eclipse.smarthome.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.java:153) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
    at org.eclipse.smarthome.core.internal.common.Invocation.call(Invocation.java:53) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
    at java.lang.Thread.run(Thread.java:748) [?:?]

On initialization of the ThingHandler we see an ERROR log which should be reduced to DEBUG level:

2018-04-17 20:53:35.526 [ERROR] [nding.network.handler.NetworkHandler] - Configuration for hostname is faulty
java.net.UnknownHostException: myphone: Der Name oder der Dienst ist nicht bekannt
        at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) ~[?:?]
        at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928) [?:?]
        at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323) [?:?]
        at java.net.InetAddress.getAllByName0(InetAddress.java:1276) [?:?]
        at java.net.InetAddress.getAllByName(InetAddress.java:1192) [?:?]
        at java.net.InetAddress.getAllByName(InetAddress.java:1126) [?:?]
        at java.net.InetAddress.getByName(InetAddress.java:1076) [?:?]
        at org.openhab.binding.network.internal.PresenceDetection.setHostname(PresenceDetection.java:96) [224:org.openhab.binding.network:2.3.0.201804141026]
        at org.openhab.binding.network.handler.NetworkHandler.initialize(NetworkHandler.java:156) [224:org.openhab.binding.network:2.3.0.201804141026]
        at org.openhab.binding.network.handler.NetworkHandler.initialize(NetworkHandler.java:202) [224:org.openhab.binding.network:2.3.0.201804141026]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:?]
        at org.eclipse.smarthome.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.java:153) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
        at org.eclipse.smarthome.core.internal.common.Invocation.call(Invocation.java:53) [103:org.eclipse.smarthome.core:0.10.0.201804131043]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:?]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
        at java.lang.Thread.run(Thread.java:748) [?:?]

[cweitkamp]

As a side note: I didn't find time to replace the ExpiringCacheAsync with the ESH implementation (see https://github.com/openhab/openhab2-addons/pull/2765#pullrequestreview-75794884). Maybe someone can give me a hand on that.

[cweitkamp]

Another one:

2018-04-19 08:51:34.243 [WARN ] [mmon.WrappedScheduledExecutorService] - Scheduled runnable ended with an exception
java.lang.NullPointerException: null
    at java.util.LinkedList$ListItr.next(LinkedList.java:893) ~[?:?]
    at org.openhab.binding.network.internal.toberemoved.cache.ExpiringCacheAsync.setValue(ExpiringCacheAsync.java:90) ~[?:?]
    at org.openhab.binding.network.internal.PresenceDetection.submitFinalResult(PresenceDetection.java:321) ~[?:?]
    at org.openhab.binding.network.internal.PresenceDetection.waitForPresenceDetection(PresenceDetection.java:350) ~[?:?]
    at org.openhab.binding.network.internal.PresenceDetection.performPresenceDetection(PresenceDetection.java:288) ~[?:?]
    at org.openhab.binding.network.internal.PresenceDetection.lambda$4(PresenceDetection.java:479) ~[?:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:?]
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [?:?]
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [?:?]
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [?:?]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?]
    at java.lang.Thread.run(Thread.java:748) [?:?]

[davidgraeff]

The OP NPE is fixed in the lasted code base. Closing this now. If the second NPE still (which might be related) still occurs, please reopen.

[cweitkamp]

@davidgraeff Agreed. They never occurred again.

Do you think we can at least take care of the replacement for the "toberemoved" class (ExpiringCacheAsync)?

[davidgraeff]

My next round of fixing will be MQTT related, the network binding is like super low on my priority list atm. But yeah at some point that class should go.