[UIMA-5973] UIMA-DUCC: fix NPE when pullservice is stopping

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-Ducc
• Component/s: DUCC
• Assignee: Jaroslaw Cwiklik
• Reporter: Jaroslaw Cwiklik
• Created: 30/Jan/19 19:32
• Updated: 30/Jan/19 21:20
• Resolved: 30/Jan/19 21:20

Description

When a service is stopping due to one thread failing in AE.process(), another thread throws NPE while handling incomplete task. Looks like transport has stopped while a thread attempted to send GET request. 

java.lang.NullPointerException
at org.apache.uima.ducc.ps.service.protocol.builtin.DefaultServiceProtocolHandler.call(DefaultServiceProtocolHandler.java:283)
at org.apache.uima.ducc.ps.service.protocol.builtin.DefaultServiceProtocolHandler.call(DefaultServiceProtocolHandler.java:55)
at java.util.concurrent.FutureTask.run(FutureTask.java:277)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:191)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1160)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at org.apache.uima.ducc.ps.ServiceThreadFactory$1.run(ServiceThreadFactory.java:57)
at java.lang.Thread.run(Thread.java:811)