On 27 Dec 2011, at 11:16, S B <sbl...@gmail.com> wrote: > On Tue, Dec 27, 2011 at 4:06 PM, Pid * <p...@pidster.com> wrote: > >> On 27 Dec 2011, at 01:33, S B <sbl...@gmail.com> wrote: >> >>> On Mon, Dec 26, 2011 at 3:28 PM, Pid * <p...@pidster.com> wrote: >>> >>>> On 26 Dec 2011, at 09:50, S B <sbl...@gmail.com> wrote: >>>> >>>>> On Sat, Dec 24, 2011 at 6:29 PM, Pid <p...@pidster.com> wrote: >>>>> >>>>>> On 23/12/2011 04:57, S B wrote: >>>>>>> On Thu, Dec 22, 2011 at 8:49 PM, Pid <p...@pidster.com> wrote: >>>>>>> >>>>>>>> On 22/12/2011 10:34, Konstantin Kolinko wrote: >>>>>>>>> 2011/12/20 S B <sbl...@gmail.com>: >>>>>>>>>> Hi, >>>>>>>>>> >>>>>>>>>> I created and deployed an MBean in my tomcat. It uses datasource >> to >>>>>>>> connect >>>>>>>>>> to DB. >>>>>>>>>> >>>>>>>>>> My questions is: >>>>>>>>>> >>>>>>>>>> When I create InitialContext() inside MBean's constructor and pass >>>> the >>>>>>>>>> envContext to DBManager class to lookup datasource it works fine. >>>>>>>> However >>>>>>>>>> when I create InitialContext() in DBManager class, it fails. >>>>>>>>> >>>>>>>>> IIRC what InitialContext() sees as its environment highly depends >> on >>>>>>>>> what classloader is active. That is TCCL = >>>>>>>>> Thread.getContextClassLoader(). >>>>>>>>> >>>>>>>>> So while it is run from within web application your TCCL = your >>>>>>>>> webapp's classloader. >>>>>>>>> >>>>>>>>> When it is invoked from jconsole it might be a separate Thread, not >>>>>>>>> related to your web application. >>>>>>>> >>>>>>>> >>>>>>>> Like he ^^^ said. :) >>>>>>>> >>>>>>>> >>>>>>>> p >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> >>>>>>>> [key:62590808] >>>>>>>> >>>>>>>> >>>>>>> Hi Pid/Konstantin, >>>>>>> >>>>>>> yes you are right. I just verified it. When it is invoked from >>>> jconsole, >>>>>>> the classloader is: sun.misc.Launcher$AppClassLoader@61e63e3d >>>>>>> and when it is run within a web application the clasloader is >>>>>>> WebAppClassloader. >>>>>>> >>>>>>> So, how can I force it to use webapp classloader during new >>>>>>> InitialContext() while invoking from jconsole >>>>>>> One possible way is to reuse the initialContext created during server >>>>>>> startup. (pass it as param during invocation from jconsole). >>>>>>> >>>>>>> Is there a smarter way ?? >>>>>> >>>>>> I am a bit concerned about how you are registering the bean inside the >>>>>> bean's own constructor. I am not clear on how you are subsequently >>>>>> unregistering that bean, before the reloading operation - and I am not >>>>>> at all clear what the purpose of reloading is anyway. >>>>>> >>>>>> Is there a reason that the MBean itself needs to be recreated? >>>>>> >>>>>> Bear in mind that you are attempting to re-initialise the MBean, while >>>>>> you are still using it. This does not seem like a good idea to me. >>>>>> >>>>>> I would suggest that you either have a separate Manager MBean that >> does >>>>>> the reloading, or just have the reload method call the actual code on >>>>>> the DB, without re-initialising the bean. >>>>>> >>>>>> >>>>>> p >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> [key:62590808] >>>>>> >>>>>> >>>>> Hi, >>>>> >>>>> un-registering of mbean doesn't happen until servlet's destroy method >> is >>>>> called. >>>>> Actually, registration of bean happen only once, ie during server >>>> startup. >>>>> This time mbean's constructor is called and it is registered with MBean >>>>> server. >>>>> (I was wrong earlier when I said, constructor is called on each >>>> invocation >>>>> of reload() method from jconsole. sorry about that. i was lill >> confused.) >>>>> >>>>> MBean is never re-created. It is created only once and registered only >>>> once. >>>>> >>>>> actual flow is: >>>>> >>>>> click reload() on jconsole gui. >>>>> *it causes constructor of MBeanImpl to run. (verified from logs.)* -- >>>> *Wrong. >>>>> pls disregard this statement.* >>>>> calls reload() defined in MBeanImpl. >>>>> calls DBManager.reload() >>>>> inside DBManager.reload() it fails at InitialContext initContext = new >>>>> InitialContext(); >>>>> the exception is - javax.naming.NoInitialContextException: Cannot >>>>> instantiate class: org.apache.naming.java.javaURLContextFactory [Root >>>>> exception is java.lang.ClassNotFoundException: >>>>> org.apache.naming.java.javaURLContextFactory] >>>> >>>> OK, but what is the purpose of DBManager.reload()? >>>> >>>> >>>> p >>>> >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >>>> For additional commands, e-mail: users-h...@tomcat.apache.org >>>> >>>> >>> >>> Hi Pid, Marry Christmas !!! >>> Purpose of DBManager.reload() is to load some application specific data >>> from DB. Pls don't consider reload() as reload of MBean. >>> reload() can better be renamed as loadData(). >>> >>> when I invoke reload() from jconsole my application is suppose to make a >> db >>> connection and load app specific data from database. >> >> OK, so why not retain a reference to the DataSource that you're >> getting the connection from? >> >> >> p >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> >> > yes. thats one possible workaround. I followed similar approach and > retailed reference of Context (which i used to get datasource during > invocation from jconsole). > This approach works. > And as Konstantin earlier said it is because of different class loaders > that I can't do "new InitialContext()" during invocation from jconsole. > *My question is: how can I force it to use webapp classloader during new > InitialContext() while invoking from jconsole.* > > is there a way to do something like > InitialContext.useClassLoader(webaappClassLoader) > ? > During server startup InitialContext() used webapp classloader and during > invocation of mbean from jconsole it was some other classloader hence " new > InitialContext()" failed. > > you got my question ?
Yes. I got it. I'm not trying to find a solution because I'm not sure why you insist on doing things the hard way when there is a perfectly reasonable alternative. p --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
