JBoss 7.1.0: executor.submit() how to debug (no exception but task not started) - jboss

Question

I have an issue with JBoss EAP 7.1.0 GA. On one server (my DEV) this works like a charm while on the other (TEST environment) the Callable executed using executor.submit() does not seem to be started (I do not see that "This is call" message in log), but no exception or any other clue is given.
The question is - where should I look like / how should I debug this issue?
The calling code:
#Resource(name = "DefaultManagedExecutorService")
ManagedExecutorService executor;
try {
DownloadPlayers dp = new DownloadPlayers();
Future<Queue<PlayerForDownload>> f = executor.submit(dp);
Queue<PlayerForDownload> q = f.get();
L.info(q.size());
} catch (Exception e) {
L.error("EXCEPTION" + e.getMessage());
}
The class it calls:
public class DownloadPlayers implements Callable<Queue<PlayerForDownload>> {
// the constructor gets called, I'm sure as it writes to log
// the call is as simple as this
#Override
public Queue<PlayerForDownload> call() {
L.info("This is call()");
try {
return this.getPlayersForDownload();
} catch (WorkerException e) {
L.error(e);
return null;
}
}
}
As stated above, the code itself seems to be OK as it works in one server but does not work on the other. Both are
7.1.0GA standalone.
Any advice how to debug the ManagedExecutorService?
Thanks.

Answer 1

In this particular case the problem was that on the TEST environment it was only allowed to run two threads which we already running (by some completely different part of application I didn't realize). So the problem is solved now by setting the "Core threads" parameter in ManagerExecutorService to higher value, the tasks are running.
However the tricky part was that there was no obvious visible difference between the JBoss servers (I compared the standalone.xml configs...) just because the ManagerExecutorService in JBoss has some default (blank) values that actually depend on the system config (v-CPU cores in my case). So despite the config being the same, the "Core threads" seem to default to 2 on TEST and some higher (unknown to me) value on my DEV.
So never depend on default settings in ManagerExecutorService if comparing two environments.
I have also rewritten the logic, instead of using blocking Future.get() or checking for Future.isDone() in a loop a do Future.get() with timeout and in the exception handler I decide whether to keep waiting or fail.