ConcurrentModificationException in EMA

Hi Team,

We recently migrated our code using TREP EMA API using jdk 1.8. After that we faced 2 times
below ConcurrentModificationException error
in PROD env and hence our process terminated. Then we had to start our service
again. Kindly help to fix this issue ASAP.

We made the connection to TREP using DACSID provided by MDS team and reference code EMA Consumer - Requesting and displaying
MarketPrice data
shared by Umer Nalla/Team.

FYI. My prev question: https://community.developers.refinitiv.com/questions/10437/socket-programming-to-trep.html?childToView=11899

java.util.ConcurrentModificationException


at java.util.HashMap$HashIterator.remove(HashMap.java:1451)


at com.thomsonreuters.ema.access.OmmBaseImpl.rsslReactorDispatchLoop(OmmBaseImpl.java:985)


at com.thomsonreuters.ema.access.OmmBaseImpl.uninitialize(OmmBaseImpl.java:258)


at com.thomsonreuters.ema.access.OmmConsumerImpl.uninitialize(OmmConsumerImpl.java:46)


at com.d3k.reuters.DealLocator.startDealService(DealLocator.java:193)


at com.d3k.reuters.DealLocator.<init>(DealLocator.java:75)


at com.d3k.reuters.ReutersStartup.startService(ReutersStartup.java:66)


at com.d3k.reuters.ReutersStartup.main(ReutersStartup.java:81)

Best Answer

  • To clarify if this is EMA bug/non-support feature or improper implementation/configuration in application level with the development team, you can submit your problem to the development directly via GitHub at

    https://github.com/thomsonreuters/Elektron-SDK/issues

    Then, click "New issue" button. Hence, you can communicate and follow up with the development team directly.

Answers