Debugging openHAB 2 / or how to view threads

Setup, Configuration and Use Runtime
1

Is there a way to attach a debugger to openHAB 2 in Eclipse? OpenHAB seems to be running out of threads in a thread pool, and I would like to see which binding is hogging all the threads. I have 5 custom bindings, so it’s very impractical to try to reproduce it, because it sometimes takes days to happen.

If it’s not possible to use a debugger, how would I go about troubleshoot something like this? When I get this condition, no command will run at all (not just the item in the output below).

2016-03-05 17:44:49.710 [WARN ] [.core.common.ThreadPoolManager:192  ] - Thread pool 'safeCall' rejected execution of class java.util.concurrent.FutureTask
2016-03-05 17:44:54.710 [DEBUG] [s.core.common.SafeMethodCaller:188  ] - Timeout of 5000ms exceeded with no thread info available.
2016-03-05 17:44:54.711 [WARN ] [.c.thing.internal.ThingManager:301  ] - Handler for thing 'folding:slot:4e43fad8' takes more than 5000ms for processing event
2016-03-05 17:44:54.711 [DEBUG] [s.core.common.SafeMethodCaller:184  ] - Timeout of 5000ms exceeded, thread ESH-safeCall-124 (1590) in state TIMED_WAITING is at sun.misc.Unsafe.park(Unsafe.java:-2).
2016-03-05 17:44:54.711 [WARN ] [.s.c.i.events.OSGiEventManager:198  ] - Dispatching event to subscriber 'org.eclipse.smarthome.core.thing.internal.ThingManager@4fa86eb0' takes more than 5000ms.
2016-03-05 17:44:54.711 [INFO ] [arthome.event.ItemCommandEvent:43   ] - Item 'folding_slot_4e43fad8_pause' received command OFF
2016-03-05 17:44:54.712 [DEBUG] [.c.thing.internal.ThingManager:290  ] - Delegating command 'OFF' for item 'folding_slot_cd16eff6_pause' to handler for channel 'folding:slot:cd16eff6:pause'
2016-03-05 17:44:54.712 [WARN ] [.core.common.ThreadPoolManager:192  ] - Thread pool 'safeCall' rejected execution of class java.util.concurrent.FutureTask
2016-03-05 17:44:59.712 [DEBUG] [s.core.common.SafeMethodCaller:188  ] - Timeout of 5000ms exceeded with no thread info available.
2016-03-05 17:44:59.712 [WARN ] [.c.thing.internal.ThingManager:301  ] - Handler for thing 'folding:slot:cd16eff6' takes more than 5000ms for processing event
2016-03-05 17:44:59.712 [DEBUG] [s.core.common.SafeMethodCaller:184  ] - Timeout of 5000ms exceeded, thread ESH-safeCall-124 (1590) in state TIMED_WAITING is at sun.misc.Unsafe.park(Unsafe.java:-2).
2

Yes, there absolutely is!
Just start the instance with start_debug.sh and it will listen to remote debugging on port 5005.
See here on how to do remote debugging of Java applications with Eclipse.

3

Thanks for the reply! With the “Addon development” setup I don’t actually have karaf where the start.sh script expects it. I did found a debug configuration in Eclipse though, which worked. That was the first thing I looked for before I posted here, so I don’t understand how I could have overlooked that. Anyway, I have debugging, so it’s all good.