On Tue, Dec 27, 2011 at 4:53 PM, Pid * <p...@pidster.com> wrote:
> 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 > > That's fine. I just wanted to confirm whether the reference-retention approach is the smartest one or there are any better solution available. Thanks for your help. :)
