This is kind of an FYI or FWIW.
I haven't implemented JNI code in a very long time. But back when I
did, it was extremely easy to write code leaked memory if you weren't
extremely careful with allocations involving objects allocated on the
native side and objects passed across the interface (regardless of where
they were allocated) and what was done with the on the other side. IIRC
the JDK has very specific instructions on what you can and can't do and
how to handle these issues. If you know what objects are leaking, find
out where they were allocated and what is being done with them
(especially if they are java objects being passed through JNI -- you may
be doing something in the native code that is damaging the reference
counts).
-Peter
Martin, Ray wrote:
> This is just FYI:
>
> I wanted to see if I could get "the EJB" out of my problem space. I do
> not know a a way to include a Java SE project into a composite app - a
> service assembly. So, I created a WebApp and copied all my code from my
> EJBModule project. I removed all EJB references and created my own
> EntityManager for persistence. I added the WebApp war file to the
> service assembly in place of the EJBModule. NetBeans 'wired' together
> the service assembly. I deployed what looks to me to be a POJO app to
> Glassfish.
>
> Making the call to the JNI causes severe memory leak. Additionally,
> which I had not mentioned prior, I cannot send any SOAP messages after
> calling the JNI. This inability to send follow-on SOAP messages
> invalidates my Glassfish show and tell.
>
> Anyway, this is just info. No response necessary. But, any useful
> advice would be appreciated.
>
> Thanx.
>
> -----Original Message-----
> From: Sanjeeb.Sahoo_at_Sun.COM [mailto:Sanjeeb.Sahoo_at_Sun.COM] On Behalf Of
> Sahoo
> Sent: Friday, May 29, 2009 8:49 AM
> To: users_at_glassfish.dev.java.net
> Subject: Re: JNI/CompositeApp/Glassfish
>
> Just because the spec says "don't do it" does not necessarily mean "it
> will not work." I am not familiar with CompositeApps, so I can't comment
> on that. What I understand from your problem description is your main
> issue is to call JNI from an EJB. I don't understand why that will not
> work. Write a simple test program and see if it works. There are certain
> things that does not work when it comes to shared libraries. A shared
> library can;t be confined to namespace of a classloader, so if you
> deploy multiple same library multiple times, things may not work. But
> then, I don't think you are trying to do that.
>
> Secondly why do you care about memory leak if you are just showing some
> feature? That can be independently addressed, no?
>
> Sahoo
>
> Martin, Ray wrote:
>
>> Yes, Mr. Chris suggested to use jmap and jhat to locate the leak. In
>> my search for how to use those tools, I found that JNI is not supposed
>>
>
>
>> to work in EJB. So, I said to myself "wow, I am trying to do stuff
>> that you are not even supposed to be doing. It does not really matter
>> whether there appears to be a leak or not - the specs say don't do
>> it." I will spend many weeks on classloaders and jhat and jmap and...
>>
>
>
>> I had a deadline to meet to show the great world of Glassfish SOA.
>>
>> I do not know how to deploy a POJO app (with a BPEL 'face') in a
>> composite app. If I knew that, I could call the JNI from the POJO
>> (staying out of that EJB world) and meet my deadline and put a smile
>> on my superiors faces. Then later, after my superiors agree that my
>> selection of Glassfish is marvelous, then I can look for memory leaks
>> or whatever. But, right now, it's killing me.
>>
>> Thanx.
>>
>> -----Original Message-----
>> From: Sanjeeb.Sahoo_at_Sun.COM [mailto:Sanjeeb.Sahoo_at_Sun.COM] On Behalf
>> Of Sahoo
>> Sent: Friday, May 29, 2009 8:07 AM
>> To: users_at_glassfish.dev.java.net
>> Subject: Re: JNI/CompositeApp/Glassfish
>>
>> Martin,
>>
>> I am confused. What's your issue? In your first posting you mentioned
>> that you were successful in running JNI code inside GlassFish except
>> that you suspected some memory leak for which Chris suggested to use
>> tools like hat. You were supposed to analyse the memory leak. Have you
>>
>
>
>> identified the cause? If yes, then tell us and tell us if it needs a
>> fix in GF.
>>
>> I have failed to identify if you have any other issue in this email
>> thread. Personally, I have not come across many use cases where a J2EE
>>
>
>
>> app uses JNI. It appears that the spec discourages use of JNI. See [1]
>>
>
>
>> for some discussion. So, over all, it should work with some
>>
> limitations.
>
>> Thanks,
>> Sahoo
>>
>> [1]
>> http://www.theserverside.com/discussions/thread.tss?thread_id=14057
>>
>> Martin, Ray wrote:
>>
>>
>>> i am readin' and scratchin' for JCA information - WOW. What a
>>> complex
>>>
>>>
>>
>>
>>> convoluted mechanism to merely call a tiny piece of code.
>>>
>>> i have many Glassfish instances running a variety of things as SOA
>>> nodes. One of the things that one of the Glassfish nodes must do is
>>> run a mathematical algorithm called a bayesian net.
>>>
>>> Why should it matter that that one instance is not portable? So, it
>>> must run on a specific hardware platform, who cares? All that is
>>> necessary is for the classloader to function properly to allow this
>>> particular non-portable code to run in a nice simplistic manner.
>>>
>>> But, no - i now am required to build my own EIS-like system to
>>> contain
>>>
>>>
>>
>>
>>> a daemon process to listen for commands to run a small algorithm.
>>> Then i need to create an adapter. Then i need to create a connector.
>>>
>>>
>>
>>
>>> Then i need to ... oh boy.
>>>
>>> And, there is something wrong with a system in which a Glassfish node
>>>
>
>
>>> performs some specialty algorithm? Hmm - yep, i am too dumb to
>>> understand that.
>>>
>>> ---------------------------------------------------------------------
>>> -
>>> --
>>> *From:* Martin, Ray
>>> *Sent:* Friday, May 29, 2009 6:22 AM
>>> *To:* users_at_glassfish.dev.java.net
>>> *Subject:* RE: RE: RE: JNI/CompositeApp/Glassfish
>>>
>>> i am too dumb to know that was a solution...
>>>
>>> ---------------------------------------------------------------------
>>> -
>>> --
>>> *From:* Markus Karg [mailto:karg_at_quipsy.de]
>>> *Sent:* Friday, May 29, 2009 6:14 AM
>>> *To:* users_at_glassfish.dev.java.net
>>> *Subject:* RE: RE: JNI/CompositeApp/Glassfish
>>>
>>> The idea of EJB is to have a portable application which runs on any
>>> application server on any operating system on any hardware platform.
>>> JNI works only with a particular operating system and hardware
>>> platform. These two core ideas are absolutely not compatible. It just
>>>
>
>
>>> makes no sense to use EJB directly with JNI. If native stuff is
>>> needed
>>>
>>>
>>
>>
>>> in an enterprise application, it has to be provided in the form of a
>>> JCA 1.5 adapter. This is the official Java EE solution to bind
>>> portable applications (EJB) to platform-specific code (JNI). What
>>> problem do you have with that?
>>>
>>>
>>>
>>> *From:* Martin, Ray [mailto:armart3_at_tycho.ncsc.mil]
>>> *Sent:* Freitag, 29. Mai 2009 12:08
>>> *To:* users_at_glassfish.dev.java.net
>>> *Subject:* RE: JNI/CompositeApp/Glassfish
>>>
>>>
>>>
>>> Very smart people created JNI.
>>>
>>> Very smart people created EJB.
>>>
>>>
>>>
>>> These very smart people make sure that JNI cannot operate within EJB
>>> -
>>>
>>>
>>
>>
>>> why would people do something like that?
>>>
>>>
>>>
>>> i have fuddled for months building a system around glassfish - now it
>>>
>
>
>>> looks like i am back to ServiceMix, where i was a year ago
>>>
>>>
>>>
>>> ---------------------------------------------------------------------
>>> -
>>> --
>>>
>>> *From:* Martin, Ray
>>> *Sent:* Thursday, May 28, 2009 12:54 PM
>>> *To:* users_at_glassfish.dev.java.net
>>> *Subject:* JNI/CompositeApp/Glassfish
>>>
>>> Does anyone have a JNI application running in Glassfish?
>>>
>>>
>>>
>>> I have a third party JNI app (Netica). It runs fine from the command
>>>
>
>
>>> line.
>>>
>>>
>>>
>>> i have an EJBModule and a BPEL project added to a composite app. The
>>>
>
>
>>> composite app is deployed to Glassfish and runs fine - receiving and
>>> responding to SOAP message.
>>>
>>>
>>>
>>> i then add the JNI app to the EJBModule and deploy the composite app
>>> to Glassfish.
>>>
>>>
>>>
>>> there are two SOAP messages to the composite app - setup and
>>>
> activate.
>
>>>
>>>
>>> i issue the setup message - the request and response occur.
>>>
>>> i issue the activate message - the JNI app runs - all is good - the
>>> results are stored in the database.
>>>
>>> after the JNI app should be completed, the memory usage starts to
>>>
>>>
>> climb.
>>
>>
>>>
>>>
>>> any suggestions?
>>>
>>>
>>>
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>>
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