NPE when PlayCollect operation is canceled prematurely by DTMF detector.
2016-05-31 03:26:48,167 INFO PlayCollect (mobicents/ivr/31) Prompt phase terminated, start collect phase
2016-05-31 03:26:49,066 INFO AudioPlayerImpl (mobicents/ivr/35) End of file reached
2016-05-31 03:26:49,066 INFO PlayCollect (mobicents/ivr/35) Processing player next with url - https://10.172.67.3:443/restcomm/cache/ACae6e420f425248d6a26948c17a9e2acf/7ed89118a42127adb7c70b4536b5d0e33ff61f4281ec232b99157ef791708bfe.wav
2016-05-31 03:26:50,186 INFO EventBuffer Receive 2 tone
2016-05-31 03:26:50,186 INFO AudioPlayerImpl (mobicents/ivr/14) End of file reached
2016-05-31 03:26:50,186 INFO PlayCollect (mobicents/ivr/14) Tone '2' has been detected
2016-05-31 03:26:50,186 INFO PlayCollect (mobicents/ivr/14) Processing player next with url - https://10.172.67.3:443/restcomm/cache/ACae6e420f425248d6a26948c17a9e2acf/7ed89118a42127adb7c70b4536b5d0e33ff61f4281ec232b99157ef791708bfe.wav
2016-05-31 03:26:50,186 INFO PlayCollect (mobicents/ivr/14) Tone '2' has been detected: prompt phase interrupted
2016-05-31 03:26:50,187 INFO DetectorImpl (mobicents/ivr/14) (detector) Delivered '2' tone
2016-05-31 03:26:50,191 ERROR Task Could not execute task 2: null
java.lang.NullPointerException
at org.mobicents.media.server.mgcp.pkg.au.PlayCollect.next(PlayCollect.java:387)
at org.mobicents.media.server.mgcp.pkg.au.PlayCollect.access$500(PlayCollect.java:62)
at org.mobicents.media.server.mgcp.pkg.au.PlayCollect$PromptHandler.process(PlayCollect.java:527)
at org.mobicents.media.server.mgcp.pkg.au.PlayCollect$PromptHandler.process(PlayCollect.java:503)
at org.mobicents.media.server.spi.listener.Listeners.dispatch(Listeners.java:117)
at org.mobicents.media.server.impl.resource.mediaplayer.audio.AudioPlayerImpl.completed(AudioPlayerImpl.java:210)
at org.mobicents.media.server.impl.AbstractSource$Worker.perform(AbstractSource.java:442)
at org.mobicents.media.server.scheduler.Task.run(Task.java:122)
at org.mobicents.media.server.scheduler.PriorityQueueScheduler$WorkerThread.run(PriorityQueueScheduler.java:424)
NPE when PlayCollect operation is canceled prematurely by DTMF detector.