After upgrade to v17 I got this error.
All my devices with strafeping service get "strafeping down" events. But the service comes up again after some minutes (see screenshot)

2015-12-04 12:14:00,537 ERROR [Poller-Thread-1-of-30] o.o.n.p.p.PollableServiceConfig: Unexpected exception while polling PollableService [PollableInterface [PollableNode [3001]:172.27.11.1]:StrafePing]. Marking service as DOWN
java.lang.NullPointerException
at org.opennms.netmgt.poller.pollables.LatencyStoringServiceMonitorAdaptor.persistLatencySamples(LatencyStoringServiceMonitorAdaptor.java:210) ~[opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.LatencyStoringServiceMonitorAdaptor.storeResponseTime(LatencyStoringServiceMonitorAdaptor.java:157) ~[opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.LatencyStoringServiceMonitorAdaptor.poll(LatencyStoringServiceMonitorAdaptor.java:121) ~[opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableServiceConfig.poll(PollableServiceConfig.java:119) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableService.poll(PollableService.java:191) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.poll(PollableElement.java:293) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableContainer$5.run(PollableContainer.java:319) [opennms-services-17.0.0.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:264) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:250) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:228) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableContainer.poll(PollableContainer.java:326) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableInterface.poll(PollableInterface.java:224) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableContainer$5.run(PollableContainer.java:319) [opennms-services-17.0.0.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:264) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:250) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:228) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableContainer.poll(PollableContainer.java:326) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableNode$3.run(PollableNode.java:331) [opennms-services-17.0.0.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:264) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:250) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:228) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableNode.doPoll(PollableNode.java:334) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.doPoll(PollableElement.java:184) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableService.doPoll(PollableService.java:226) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableService$PollRunner.run(PollableService.java:63) [opennms-services-17.0.0.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:264) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableElement.withTreeLock(PollableElement.java:250) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableService.doRun(PollableService.java:413) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.poller.pollables.PollableService.run(PollableService.java:388) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.scheduler.Schedule.run(Schedule.java:142) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.scheduler.Schedule$ScheduleEntry.run(Schedule.java:86) [opennms-services-17.0.0.jar:?]
at org.opennms.netmgt.scheduler.LegacyScheduler$1.run(LegacyScheduler.java:209) [opennms-services-17.0.0.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_45]
at org.opennms.core.concurrent.LogPreservingThreadFactory$3.run(LogPreservingThreadFactory.java:124) [opennms-util-17.0.0.jar:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]