The purpose of the J2EE thread model is to prevent prevent custom threads from interacting with container threads. I believe that it is the intention to protect against data corruption issues, data visibility issues etc. If it was allowed for custom threads to call servlet or EJB methods concurrently with calls from container threads, it would be impossible to make thread-safe J2EE apps.
What Log4j and various other libraries do is create helper threads to offload processing from the container threads. As long as our threads don't call back into the application the thread-safety risks are manageable. We essentially rely on people to not do crazy stuff in their toString() methods. As far as I am aware, any "worker thread" frameworks provided by J2EE containers are not designed for performance requirements like ours. They also don't solve any issues with objects doing crazy stuff in their toString() method. So practically speaking there's only drawbacks and no benefits for Log4j to adhere to the letter of the specification. We do adhere to the spirit of it though. Frankly speaking I think this part of the J2EE spec was not very well thought out. I think this is one of the reasons we will see reactive frameworks like Akka and ReactiveX take market share in spaces where J2EE now dominates. Sent from my iPhone > On 2016/07/15, at 6:36, Paul Benedict <[email protected]> wrote: > > Ralph, I am sure it does require some refactoring. Sounds like a good 3.0 > thing :-) but it would be really awesome if Log4J could advertise itself as > EE compatible with threading. Just my 2 cents. When it comes to the > refactoring, you'll just want to have a good abstraction built so you can > plug in the right implementation at runtime (non-container vs container). > > Cheers, > Paul > >> On Thu, Jul 14, 2016 at 4:34 PM, Ralph Goers <[email protected]> >> wrote: >> I’m not aware that frameworks like Log4j actually adhere to those >> guidelines. It is too difficult to write code that works in both the JEE and >> non-JEE environments. >> >> Ralph >> >>> On Jul 14, 2016, at 1:07 PM, Paul Benedict <[email protected]> wrote: >>> >>> In an EE environment, don't create your own threads. If you do create your >>> own threads, the EE server has no way to shut them down when an application >>> gets undeployed. You'd want to have the EE server manage the thread >>> creations. >>> >>> Cheers, >>> Paul >>> >>>> On Thu, Jul 14, 2016 at 2:41 PM, Gary Gregory <[email protected]> >>>> wrote: >>>> I'll get around to it ;-) >>>> >>>> Gary >>>> >>>>> On Thu, Jul 14, 2016 at 11:35 AM, Matt Sicker <[email protected]> wrote: >>>>> Anyone wanna make a jira ticket for this? I'm not sure on how best to >>>>> describe this. >>>>> >>>>>> On 5 July 2016 at 09:00, Matt Sicker <[email protected]> wrote: >>>>>> I'm not sure how many threads we spawn are actually reusable, but >>>>>> gathering them into a single pool would definitely help figure out which >>>>>> ones can be used. >>>>>> >>>>>> Also, would this be vaguely related to the custom Log4j ThreadLocal >>>>>> object we were thinking about a little while ago? >>>>>> >>>>>>> On 5 July 2016 at 04:52, Mikael Ståldal <[email protected]> >>>>>>> wrote: >>>>>>> Sounds like a good idea. I think it's also good to reuse threads for >>>>>>> performance. >>>>>>> >>>>>>>> On Mon, Jul 4, 2016 at 10:00 PM, Matt Sicker <[email protected]> wrote: >>>>>>>> This sounds like an interesting idea worth pursuing. >>>>>>>> >>>>>>>>> On 4 July 2016 at 14:56, Gary Gregory <[email protected]> wrote: >>>>>>>>> When I see code like: >>>>>>>>> >>>>>>>>> LOGGER.debug("RollingFileManager executing async >>>>>>>>> {}", descriptor.getAsynchronous()); >>>>>>>>> thread = new Log4jThread(new >>>>>>>>> AsyncAction(descriptor.getAsynchronous(), this)); >>>>>>>>> thread.start(); >>>>>>>>> >>>>>>>>> and: >>>>>>>>> >>>>>>>>> final Thread thread = new Log4jThread(new >>>>>>>>> ReconfigurationWorker(listener, reconfigurable)); >>>>>>>>> thread.setDaemon(true); >>>>>>>>> thread.start(); >>>>>>>>> >>>>>>>>> and other places, I think: "and poof, I've lost track of that thread". >>>>>>>>> >>>>>>>>> What if we used a thread pool (ExecutorService) to track all of our >>>>>>>>> threads? This would allow for at least trying for an orderly >>>>>>>>> shutdown. This would avoid problems like one part of an app thinking >>>>>>>>> that rollovers should be done when they are not because a log4j >>>>>>>>> context has been stopped (like in our test probably) but the rollover >>>>>>>>> thread is still going about doing its work. >>>>>>>>> >>>>>>>>> This would be for 2.7 I think. >>>>>>>>> >>>>>>>>> We could then have a different context stop API, maybe with a timeout >>>>>>>>> or not, something like ExecutorService's shutdown() vs. shutdownNow(). >>>>>>>>> >>>>>>>>> Thoughts? >>>>>>>>> >>>>>>>>> Happy 4th! >>>>>>>>> >>>>>>>>> Gary >>>>>>>>> >>>>>>>>> -- >>>>>>>>> E-Mail: [email protected] | [email protected] >>>>>>>>> Java Persistence with Hibernate, Second Edition >>>>>>>>> JUnit in Action, Second Edition >>>>>>>>> Spring Batch in Action >>>>>>>>> Blog: http://garygregory.wordpress.com >>>>>>>>> Home: http://garygregory.com/ >>>>>>>>> Tweet! http://twitter.com/GaryGregory >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Matt Sicker <[email protected]> >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> >>>>>>> >>>>>>> Mikael Ståldal >>>>>>> Senior software developer >>>>>>> >>>>>>> Magine TV >>>>>>> [email protected] >>>>>>> Grev Turegatan 3 | 114 46 Stockholm, Sweden | www.magine.com >>>>>>> >>>>>>> Privileged and/or Confidential Information may be contained in this >>>>>>> message. If you are not the addressee indicated in this message >>>>>>> (or responsible for delivery of the message to such a person), you may >>>>>>> not copy or deliver this message to anyone. In such case, >>>>>>> you should destroy this message and kindly notify the sender by reply >>>>>>> email. >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Matt Sicker <[email protected]> >>>>> >>>>> >>>>> >>>>> -- >>>>> Matt Sicker <[email protected]> >>>> >>>> >>>> >>>> -- >>>> E-Mail: [email protected] | [email protected] >>>> Java Persistence with Hibernate, Second Edition >>>> JUnit in Action, Second Edition >>>> Spring Batch in Action >>>> Blog: http://garygregory.wordpress.com >>>> Home: http://garygregory.com/ >>>> Tweet! http://twitter.com/GaryGregory >
