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Posted to user@commons.apache.org by rmenon <rm...@gmail.com> on 2009/01/03 20:14:45 UTC
Digester 1.8 classloader issue when using tomcat
Hi
I have three jar files: common, webapp-common, my-webapp.jar.
common- can be used by non web apps
webapp-common - common stuff shared by web apps.
my-webapp.jar - a particular web app.
I am using digester to build my classes for the app my-webapp.jar. In the
digester rules, I have classes that are in all three jar files. Now, ideally
speaking, I should be able to put the webapp-cmmon and common jar files in
the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that results
in the digester failing with "NoClassDefFoundException". The problem goes
away if we put all three jars in the WEB-INF/lib since the digester class
loader can see those classes. However, the common jar is already in the
shared/lib being used by other apps. I added some new "common" stuff for the
my-webapp.jar and hence running into this issue.
My latest thinking is to separate out the portion of the classes being used
by the my-webapp.jar from the common jar file into its own jar. Then I can
bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and retain
the common jar in the shared/lib. Is there a better approach? What is the
best practice in this scenario. Does someone have an idea of overhead in
terms of performance etc if we "duplicate" jar files in each app instead of
sharing them in common/lib? What I do not like about this issue is that I
think this issue would not be there if I was creating objects without using
digester - so a way to use the approach (where I can access the common
classes from digester) would be really ideal in my opinion.
I did search the google and also this forum - I note that someone suggested
to always bundle each jar files within the web app itself separately. What
is the rationale for that?
Thank you!
I saw a suggestion here where someone suggested that
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
Well,
Can you please elaborate a bit more? My question is why should we reload the
same classes multiple times for a jar file that is shared by multiple web
apps? Also, if I do not use digester, then this is not an issue - so what
are people who use digester doing (apart from duplicating war files)? I do
not like the idea of duplicating same war files for each web app - so is
there a good reason to do that (apart from being a workaround for problems
with digester)?
Thanx for responding...
Rahul Akolkar wrote:
>
> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>
>> Can you please elaborate? Are you suggesting that I should just package
>> all
>> three jar files in WEB-INF/lib?
>>
> <snip/>
>
> If they are needed by the said web app, yes.
>
> -Rahul
>
>
>> Rahul Akolkar wrote:
>>>
>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>
>>>> Hi
>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>> common- can be used by non web apps
>>>> webapp-common - common stuff shared by web apps.
>>>> my-webapp.jar - a particular web app.
>>>>
>>>> I am using digester to build my classes for the app my-webapp.jar. In
>>>> the
>>>> digester rules, I have classes that are in all three jar files. Now,
>>>> ideally
>>>> speaking, I should be able to put the webapp-cmmon and common jar files
>>>> in
>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>> results
>>>> in the digester failing with "NoClassDefFoundException". The problem
>>>> goes
>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>> class
>>>> loader can see those classes. However, the common jar is already in the
>>>> shared/lib being used by other apps. I added some new "common" stuff
>>>> for
>>>> the
>>>> my-webapp.jar and hence running into this issue.
>>>>
>>>> My latest thinking is to separate out the portion of the classes being
>>>> used
>>>> by the my-webapp.jar from the common jar file into its own jar. Then I
>>>> can
>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>> retain
>>>> the common jar in the shared/lib. Is there a better approach? What is
>>>> the
>>>> best practice in this scenario. Does someone have an idea of overhead
>>>> in
>>>> terms of performance etc if we "duplicate" jar files in each app
>>>> instead
>>>> of
>>>> sharing them in common/lib? What I do not like about this issue is that
>>>> I
>>>> think this issue would not be there if I was creating objects without
>>>> using
>>>> digester - so a way to use the approach (where I can access the common
>>>> classes from digester) would be really ideal in my opinion.
>>>>
>>>> I did search the google and also this forum - I note that someone
>>>> suggested
>>>> to always bundle each jar files within the web app itself separately.
>>>> What
>>>> is the rationale for that?
>>>>
>>> <snip/>
>>>
>>> Portability, potential trouble with statics etc. Also, digester itself
>>> (and beanutils in particular) should never be shared.
>>>
>>> -Rahul
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
>>> For additional commands, e-mail: user-help@commons.apache.org
>>>
>>>
>>>
>>
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>> http://www.nabble.com/Digester-1.8-classloader-issue-when-using-tomcat-tp21268177p21269147.html
>> Sent from the Commons - User mailing list archive at Nabble.com.
>>
>>
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>>
>>
>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
I did try to use the method setUseContextClassLoader in Digester - but it
started giving me a "ClassCastException"...
And, I do see what your recommendation is but I am not convinced of the
justification given.
Thanx.
Menon
Rahul Akolkar wrote:
>
> On Sun, Jan 4, 2009 at 10:47 AM, rmenon <rm...@gmail.com> wrote:
>>
>> Thank you
>> Now I understand what Rahul meant by "portable". Chances of our changing
>> web servers is slim.
>>
>> Well, if I had not used digester, I could have put the common war file in
>> the shared/lib. I am ok with not sharing digester itself but the fact
>> that
>> all the digester constructed classes need to be put in WEB-INF/lib seems
>> to
>> be a severe restriction to me.
> <snip/>
>
> Rather, its a strong recommendation.
>
> Have you tried using the thread context class loader?
>
> -Rahul
>
>
>> By the way, has anyone done an analysis of how much it costs to duplicate
>> the war files in terms of memory?
>>
>> Thanx again for the reply to you and Rahul.
>>
>> Menon
>>
>> jwcarman wrote:
>>>
>>> BeanUtils (which Digester uses) uses static variables, so sharing that
>>> particular stuff across webapps can cause some trouble. As Rahul
>>> said, just put the stuff in your WEB-INF/lib directory. It's more
>>> portable that way (you can just plop your war file down in any other
>>> web server if it's constructed this way).
>>>
>>> On Sat, Jan 3, 2009 at 5:27 PM, rmenon <rm...@gmail.com> wrote:
>>>>
>>>>
>>>>
>>>> Rahul Akolkar wrote:
>>>>>
>>>>> On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>
>>>>>> Well,
>>>>>> Can you please elaborate a bit more? My question is why should we
>>>>>> reload
>>>>>> the
>>>>>> same classes multiple times for a jar file that is shared by multiple
>>>>>> web
>>>>>> apps?
>>>>> <snip/>
>>>>>
>>>>> Generally you want your apps to be self-contained. The servlet
>>>>> specification talks about the web app and its directory structure,
>>>>> shared stuff is often container specific (I did mention portability).
>>>>>
>>>>>
>>>>> Well, from what I understand, at least in tomcat (which is what we
>>>>> use),
>>>>> there is a shared/lib
>>>>> directory for jars that are common across applications. These jars
>>>>> need
>>>>> not be container specific.
>>>>>
>>>>>
>>>>> And I am not sure what you mean portability? Could you explain a bit
>>>>> more?
>>>>>
>>>>>> Also, if I do not use digester, then this is not an issue - so what
>>>>>> are people who use digester doing (apart from duplicating war files)?
>>>>> <snap/>
>>>>>
>>>>> I think you mean duplicating libraries in war files for different web
>>>>> apps with similar application dependencies.
>>>>>
>>>>> I meant duplicating a jar file that is shared across applications in
>>>>> each
>>>>> of the applications's WEB-INF/lib
>>>>> directories. I would think that there should be a way to put them in
>>>>> shared/lib directory and still be able to use digester to construct
>>>>> them.
>>>>>
>>>>>
>>>>>> I do
>>>>>> not like the idea of duplicating same war files for each web app - so
>>>>>> is
>>>>>> there a good reason to do that (apart from being a workaround for
>>>>>> problems
>>>>>> with digester.)
>>>>>>
>>>>> <snap/>
>>>>>
>>>>> I still think you mean adding the same jars to each WEB-INF/lib -- its
>>>>> portable and its safe.
>>>>>
>>>>> -Rahul
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>> Rahul Akolkar wrote:
>>>>>>>
>>>>>>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>>>
>>>>>>>> Can you please elaborate? Are you suggesting that I should just
>>>>>>>> package
>>>>>>>> all
>>>>>>>> three jar files in WEB-INF/lib?
>>>>>>>>
>>>>>>> <snip/>
>>>>>>>
>>>>>>> If they are needed by the said web app, yes.
>>>>>>>
>>>>>>> -Rahul
>>>>>>>
>>>>>>>
>>>>>>>> Rahul Akolkar wrote:
>>>>>>>>>
>>>>>>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> Hi
>>>>>>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>>>>>>> common- can be used by non web apps
>>>>>>>>>> webapp-common - common stuff shared by web apps.
>>>>>>>>>> my-webapp.jar - a particular web app.
>>>>>>>>>>
>>>>>>>>>> I am using digester to build my classes for the app
>>>>>>>>>> my-webapp.jar.
>>>>>>>>>> In
>>>>>>>>>> the
>>>>>>>>>> digester rules, I have classes that are in all three jar files.
>>>>>>>>>> Now,
>>>>>>>>>> ideally
>>>>>>>>>> speaking, I should be able to put the webapp-cmmon and common jar
>>>>>>>>>> files
>>>>>>>>>> in
>>>>>>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However,
>>>>>>>>>> that
>>>>>>>>>> results
>>>>>>>>>> in the digester failing with "NoClassDefFoundException". The
>>>>>>>>>> problem
>>>>>>>>>> goes
>>>>>>>>>> away if we put all three jars in the WEB-INF/lib since the
>>>>>>>>>> digester
>>>>>>>>>> class
>>>>>>>>>> loader can see those classes. However, the common jar is already
>>>>>>>>>> in
>>>>>>>>>> the
>>>>>>>>>> shared/lib being used by other apps. I added some new "common"
>>>>>>>>>> stuff
>>>>>>>>>> for
>>>>>>>>>> the
>>>>>>>>>> my-webapp.jar and hence running into this issue.
>>>>>>>>>>
>>>>>>>>>> My latest thinking is to separate out the portion of the classes
>>>>>>>>>> being
>>>>>>>>>> used
>>>>>>>>>> by the my-webapp.jar from the common jar file into its own jar.
>>>>>>>>>> Then
>>>>>>>>>> I
>>>>>>>>>> can
>>>>>>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib
>>>>>>>>>> and
>>>>>>>>>> retain
>>>>>>>>>> the common jar in the shared/lib. Is there a better approach?
>>>>>>>>>> What
>>>>>>>>>> is
>>>>>>>>>> the
>>>>>>>>>> best practice in this scenario. Does someone have an idea of
>>>>>>>>>> overhead
>>>>>>>>>> in
>>>>>>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>>>>>>> instead
>>>>>>>>>> of
>>>>>>>>>> sharing them in common/lib? What I do not like about this issue
>>>>>>>>>> is
>>>>>>>>>> that
>>>>>>>>>> I
>>>>>>>>>> think this issue would not be there if I was creating objects
>>>>>>>>>> without
>>>>>>>>>> using
>>>>>>>>>> digester - so a way to use the approach (where I can access the
>>>>>>>>>> common
>>>>>>>>>> classes from digester) would be really ideal in my opinion.
>>>>>>>>>>
>>>>>>>>>> I did search the google and also this forum - I note that someone
>>>>>>>>>> suggested
>>>>>>>>>> to always bundle each jar files within the web app itself
>>>>>>>>>> separately.
>>>>>>>>>> What
>>>>>>>>>> is the rationale for that?
>>>>>>>>>>
>>>>>>>>> <snip/>
>>>>>>>>>
>>>>>>>>> Portability, potential trouble with statics etc. Also, digester
>>>>>>>>> itself
>>>>>>>>> (and beanutils in particular) should never be shared.
>>>>>>>>>
>>>>>>>>> -Rahul
>>>>>>>>>
>>>>>
>
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> For additional commands, e-mail: user-help@commons.apache.org
>
>
>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by Rahul Akolkar <ra...@gmail.com>.
On Sun, Jan 4, 2009 at 10:47 AM, rmenon <rm...@gmail.com> wrote:
>
> Thank you
> Now I understand what Rahul meant by "portable". Chances of our changing
> web servers is slim.
>
> Well, if I had not used digester, I could have put the common war file in
> the shared/lib. I am ok with not sharing digester itself but the fact that
> all the digester constructed classes need to be put in WEB-INF/lib seems to
> be a severe restriction to me.
<snip/>
Rather, its a strong recommendation.
Have you tried using the thread context class loader?
-Rahul
> By the way, has anyone done an analysis of how much it costs to duplicate
> the war files in terms of memory?
>
> Thanx again for the reply to you and Rahul.
>
> Menon
>
> jwcarman wrote:
>>
>> BeanUtils (which Digester uses) uses static variables, so sharing that
>> particular stuff across webapps can cause some trouble. As Rahul
>> said, just put the stuff in your WEB-INF/lib directory. It's more
>> portable that way (you can just plop your war file down in any other
>> web server if it's constructed this way).
>>
>> On Sat, Jan 3, 2009 at 5:27 PM, rmenon <rm...@gmail.com> wrote:
>>>
>>>
>>>
>>> Rahul Akolkar wrote:
>>>>
>>>> On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>>>>>
>>>>> Well,
>>>>> Can you please elaborate a bit more? My question is why should we
>>>>> reload
>>>>> the
>>>>> same classes multiple times for a jar file that is shared by multiple
>>>>> web
>>>>> apps?
>>>> <snip/>
>>>>
>>>> Generally you want your apps to be self-contained. The servlet
>>>> specification talks about the web app and its directory structure,
>>>> shared stuff is often container specific (I did mention portability).
>>>>
>>>>
>>>> Well, from what I understand, at least in tomcat (which is what we use),
>>>> there is a shared/lib
>>>> directory for jars that are common across applications. These jars need
>>>> not be container specific.
>>>>
>>>>
>>>> And I am not sure what you mean portability? Could you explain a bit
>>>> more?
>>>>
>>>>> Also, if I do not use digester, then this is not an issue - so what
>>>>> are people who use digester doing (apart from duplicating war files)?
>>>> <snap/>
>>>>
>>>> I think you mean duplicating libraries in war files for different web
>>>> apps with similar application dependencies.
>>>>
>>>> I meant duplicating a jar file that is shared across applications in
>>>> each
>>>> of the applications's WEB-INF/lib
>>>> directories. I would think that there should be a way to put them in
>>>> shared/lib directory and still be able to use digester to construct
>>>> them.
>>>>
>>>>
>>>>> I do
>>>>> not like the idea of duplicating same war files for each web app - so
>>>>> is
>>>>> there a good reason to do that (apart from being a workaround for
>>>>> problems
>>>>> with digester.)
>>>>>
>>>> <snap/>
>>>>
>>>> I still think you mean adding the same jars to each WEB-INF/lib -- its
>>>> portable and its safe.
>>>>
>>>> -Rahul
>>>>
>>>>
>>>>>
>>>>>
>>>>> Rahul Akolkar wrote:
>>>>>>
>>>>>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>>
>>>>>>> Can you please elaborate? Are you suggesting that I should just
>>>>>>> package
>>>>>>> all
>>>>>>> three jar files in WEB-INF/lib?
>>>>>>>
>>>>>> <snip/>
>>>>>>
>>>>>> If they are needed by the said web app, yes.
>>>>>>
>>>>>> -Rahul
>>>>>>
>>>>>>
>>>>>>> Rahul Akolkar wrote:
>>>>>>>>
>>>>>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>>>>
>>>>>>>>> Hi
>>>>>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>>>>>> common- can be used by non web apps
>>>>>>>>> webapp-common - common stuff shared by web apps.
>>>>>>>>> my-webapp.jar - a particular web app.
>>>>>>>>>
>>>>>>>>> I am using digester to build my classes for the app my-webapp.jar.
>>>>>>>>> In
>>>>>>>>> the
>>>>>>>>> digester rules, I have classes that are in all three jar files.
>>>>>>>>> Now,
>>>>>>>>> ideally
>>>>>>>>> speaking, I should be able to put the webapp-cmmon and common jar
>>>>>>>>> files
>>>>>>>>> in
>>>>>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>>>>>>> results
>>>>>>>>> in the digester failing with "NoClassDefFoundException". The
>>>>>>>>> problem
>>>>>>>>> goes
>>>>>>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>>>>>>> class
>>>>>>>>> loader can see those classes. However, the common jar is already in
>>>>>>>>> the
>>>>>>>>> shared/lib being used by other apps. I added some new "common"
>>>>>>>>> stuff
>>>>>>>>> for
>>>>>>>>> the
>>>>>>>>> my-webapp.jar and hence running into this issue.
>>>>>>>>>
>>>>>>>>> My latest thinking is to separate out the portion of the classes
>>>>>>>>> being
>>>>>>>>> used
>>>>>>>>> by the my-webapp.jar from the common jar file into its own jar.
>>>>>>>>> Then
>>>>>>>>> I
>>>>>>>>> can
>>>>>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>>>>>>> retain
>>>>>>>>> the common jar in the shared/lib. Is there a better approach? What
>>>>>>>>> is
>>>>>>>>> the
>>>>>>>>> best practice in this scenario. Does someone have an idea of
>>>>>>>>> overhead
>>>>>>>>> in
>>>>>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>>>>>> instead
>>>>>>>>> of
>>>>>>>>> sharing them in common/lib? What I do not like about this issue is
>>>>>>>>> that
>>>>>>>>> I
>>>>>>>>> think this issue would not be there if I was creating objects
>>>>>>>>> without
>>>>>>>>> using
>>>>>>>>> digester - so a way to use the approach (where I can access the
>>>>>>>>> common
>>>>>>>>> classes from digester) would be really ideal in my opinion.
>>>>>>>>>
>>>>>>>>> I did search the google and also this forum - I note that someone
>>>>>>>>> suggested
>>>>>>>>> to always bundle each jar files within the web app itself
>>>>>>>>> separately.
>>>>>>>>> What
>>>>>>>>> is the rationale for that?
>>>>>>>>>
>>>>>>>> <snip/>
>>>>>>>>
>>>>>>>> Portability, potential trouble with statics etc. Also, digester
>>>>>>>> itself
>>>>>>>> (and beanutils in particular) should never be shared.
>>>>>>>>
>>>>>>>> -Rahul
>>>>>>>>
>>>>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
Thank you
Now I understand what Rahul meant by "portable". Chances of our changing
web servers is slim.
Well, if I had not used digester, I could have put the common war file in
the shared/lib. I am ok with not sharing digester itself but the fact that
all the digester constructed classes need to be put in WEB-INF/lib seems to
be a severe restriction to me.
By the way, has anyone done an analysis of how much it costs to duplicate
the war files in terms of memory?
Thanx again for the reply to you and Rahul.
Menon
jwcarman wrote:
>
> BeanUtils (which Digester uses) uses static variables, so sharing that
> particular stuff across webapps can cause some trouble. As Rahul
> said, just put the stuff in your WEB-INF/lib directory. It's more
> portable that way (you can just plop your war file down in any other
> web server if it's constructed this way).
>
> On Sat, Jan 3, 2009 at 5:27 PM, rmenon <rm...@gmail.com> wrote:
>>
>>
>>
>> Rahul Akolkar wrote:
>>>
>>> On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>>>>
>>>> Well,
>>>> Can you please elaborate a bit more? My question is why should we
>>>> reload
>>>> the
>>>> same classes multiple times for a jar file that is shared by multiple
>>>> web
>>>> apps?
>>> <snip/>
>>>
>>> Generally you want your apps to be self-contained. The servlet
>>> specification talks about the web app and its directory structure,
>>> shared stuff is often container specific (I did mention portability).
>>>
>>>
>>> Well, from what I understand, at least in tomcat (which is what we use),
>>> there is a shared/lib
>>> directory for jars that are common across applications. These jars need
>>> not be container specific.
>>>
>>>
>>> And I am not sure what you mean portability? Could you explain a bit
>>> more?
>>>
>>>> Also, if I do not use digester, then this is not an issue - so what
>>>> are people who use digester doing (apart from duplicating war files)?
>>> <snap/>
>>>
>>> I think you mean duplicating libraries in war files for different web
>>> apps with similar application dependencies.
>>>
>>> I meant duplicating a jar file that is shared across applications in
>>> each
>>> of the applications's WEB-INF/lib
>>> directories. I would think that there should be a way to put them in
>>> shared/lib directory and still be able to use digester to construct
>>> them.
>>>
>>>
>>>> I do
>>>> not like the idea of duplicating same war files for each web app - so
>>>> is
>>>> there a good reason to do that (apart from being a workaround for
>>>> problems
>>>> with digester.)
>>>>
>>> <snap/>
>>>
>>> I still think you mean adding the same jars to each WEB-INF/lib -- its
>>> portable and its safe.
>>>
>>> -Rahul
>>>
>>>
>>>>
>>>>
>>>> Rahul Akolkar wrote:
>>>>>
>>>>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>
>>>>>> Can you please elaborate? Are you suggesting that I should just
>>>>>> package
>>>>>> all
>>>>>> three jar files in WEB-INF/lib?
>>>>>>
>>>>> <snip/>
>>>>>
>>>>> If they are needed by the said web app, yes.
>>>>>
>>>>> -Rahul
>>>>>
>>>>>
>>>>>> Rahul Akolkar wrote:
>>>>>>>
>>>>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>>>
>>>>>>>> Hi
>>>>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>>>>> common- can be used by non web apps
>>>>>>>> webapp-common - common stuff shared by web apps.
>>>>>>>> my-webapp.jar - a particular web app.
>>>>>>>>
>>>>>>>> I am using digester to build my classes for the app my-webapp.jar.
>>>>>>>> In
>>>>>>>> the
>>>>>>>> digester rules, I have classes that are in all three jar files.
>>>>>>>> Now,
>>>>>>>> ideally
>>>>>>>> speaking, I should be able to put the webapp-cmmon and common jar
>>>>>>>> files
>>>>>>>> in
>>>>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>>>>>> results
>>>>>>>> in the digester failing with "NoClassDefFoundException". The
>>>>>>>> problem
>>>>>>>> goes
>>>>>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>>>>>> class
>>>>>>>> loader can see those classes. However, the common jar is already in
>>>>>>>> the
>>>>>>>> shared/lib being used by other apps. I added some new "common"
>>>>>>>> stuff
>>>>>>>> for
>>>>>>>> the
>>>>>>>> my-webapp.jar and hence running into this issue.
>>>>>>>>
>>>>>>>> My latest thinking is to separate out the portion of the classes
>>>>>>>> being
>>>>>>>> used
>>>>>>>> by the my-webapp.jar from the common jar file into its own jar.
>>>>>>>> Then
>>>>>>>> I
>>>>>>>> can
>>>>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>>>>>> retain
>>>>>>>> the common jar in the shared/lib. Is there a better approach? What
>>>>>>>> is
>>>>>>>> the
>>>>>>>> best practice in this scenario. Does someone have an idea of
>>>>>>>> overhead
>>>>>>>> in
>>>>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>>>>> instead
>>>>>>>> of
>>>>>>>> sharing them in common/lib? What I do not like about this issue is
>>>>>>>> that
>>>>>>>> I
>>>>>>>> think this issue would not be there if I was creating objects
>>>>>>>> without
>>>>>>>> using
>>>>>>>> digester - so a way to use the approach (where I can access the
>>>>>>>> common
>>>>>>>> classes from digester) would be really ideal in my opinion.
>>>>>>>>
>>>>>>>> I did search the google and also this forum - I note that someone
>>>>>>>> suggested
>>>>>>>> to always bundle each jar files within the web app itself
>>>>>>>> separately.
>>>>>>>> What
>>>>>>>> is the rationale for that?
>>>>>>>>
>>>>>>> <snip/>
>>>>>>>
>>>>>>> Portability, potential trouble with statics etc. Also, digester
>>>>>>> itself
>>>>>>> (and beanutils in particular) should never be shared.
>>>>>>>
>>>>>>> -Rahul
>>>>>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
>>> For additional commands, e-mail: user-help@commons.apache.org
>>>
>>>
>>>
>>
>> --
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Re: Digester 1.8 classloader issue when using tomcat
Posted by James Carman <ja...@carmanconsulting.com>.
BeanUtils (which Digester uses) uses static variables, so sharing that
particular stuff across webapps can cause some trouble. As Rahul
said, just put the stuff in your WEB-INF/lib directory. It's more
portable that way (you can just plop your war file down in any other
web server if it's constructed this way).
On Sat, Jan 3, 2009 at 5:27 PM, rmenon <rm...@gmail.com> wrote:
>
>
>
> Rahul Akolkar wrote:
>>
>> On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>>>
>>> Well,
>>> Can you please elaborate a bit more? My question is why should we reload
>>> the
>>> same classes multiple times for a jar file that is shared by multiple web
>>> apps?
>> <snip/>
>>
>> Generally you want your apps to be self-contained. The servlet
>> specification talks about the web app and its directory structure,
>> shared stuff is often container specific (I did mention portability).
>>
>>
>> Well, from what I understand, at least in tomcat (which is what we use),
>> there is a shared/lib
>> directory for jars that are common across applications. These jars need
>> not be container specific.
>>
>>
>> And I am not sure what you mean portability? Could you explain a bit more?
>>
>>> Also, if I do not use digester, then this is not an issue - so what
>>> are people who use digester doing (apart from duplicating war files)?
>> <snap/>
>>
>> I think you mean duplicating libraries in war files for different web
>> apps with similar application dependencies.
>>
>> I meant duplicating a jar file that is shared across applications in each
>> of the applications's WEB-INF/lib
>> directories. I would think that there should be a way to put them in
>> shared/lib directory and still be able to use digester to construct them.
>>
>>
>>> I do
>>> not like the idea of duplicating same war files for each web app - so is
>>> there a good reason to do that (apart from being a workaround for
>>> problems
>>> with digester.)
>>>
>> <snap/>
>>
>> I still think you mean adding the same jars to each WEB-INF/lib -- its
>> portable and its safe.
>>
>> -Rahul
>>
>>
>>>
>>>
>>> Rahul Akolkar wrote:
>>>>
>>>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>>>
>>>>> Can you please elaborate? Are you suggesting that I should just package
>>>>> all
>>>>> three jar files in WEB-INF/lib?
>>>>>
>>>> <snip/>
>>>>
>>>> If they are needed by the said web app, yes.
>>>>
>>>> -Rahul
>>>>
>>>>
>>>>> Rahul Akolkar wrote:
>>>>>>
>>>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>>
>>>>>>> Hi
>>>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>>>> common- can be used by non web apps
>>>>>>> webapp-common - common stuff shared by web apps.
>>>>>>> my-webapp.jar - a particular web app.
>>>>>>>
>>>>>>> I am using digester to build my classes for the app my-webapp.jar.
>>>>>>> In
>>>>>>> the
>>>>>>> digester rules, I have classes that are in all three jar files. Now,
>>>>>>> ideally
>>>>>>> speaking, I should be able to put the webapp-cmmon and common jar
>>>>>>> files
>>>>>>> in
>>>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>>>>> results
>>>>>>> in the digester failing with "NoClassDefFoundException". The problem
>>>>>>> goes
>>>>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>>>>> class
>>>>>>> loader can see those classes. However, the common jar is already in
>>>>>>> the
>>>>>>> shared/lib being used by other apps. I added some new "common" stuff
>>>>>>> for
>>>>>>> the
>>>>>>> my-webapp.jar and hence running into this issue.
>>>>>>>
>>>>>>> My latest thinking is to separate out the portion of the classes
>>>>>>> being
>>>>>>> used
>>>>>>> by the my-webapp.jar from the common jar file into its own jar. Then
>>>>>>> I
>>>>>>> can
>>>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>>>>> retain
>>>>>>> the common jar in the shared/lib. Is there a better approach? What is
>>>>>>> the
>>>>>>> best practice in this scenario. Does someone have an idea of overhead
>>>>>>> in
>>>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>>>> instead
>>>>>>> of
>>>>>>> sharing them in common/lib? What I do not like about this issue is
>>>>>>> that
>>>>>>> I
>>>>>>> think this issue would not be there if I was creating objects without
>>>>>>> using
>>>>>>> digester - so a way to use the approach (where I can access the
>>>>>>> common
>>>>>>> classes from digester) would be really ideal in my opinion.
>>>>>>>
>>>>>>> I did search the google and also this forum - I note that someone
>>>>>>> suggested
>>>>>>> to always bundle each jar files within the web app itself separately.
>>>>>>> What
>>>>>>> is the rationale for that?
>>>>>>>
>>>>>> <snip/>
>>>>>>
>>>>>> Portability, potential trouble with statics etc. Also, digester itself
>>>>>> (and beanutils in particular) should never be shared.
>>>>>>
>>>>>> -Rahul
>>>>>>
>>
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>> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
>> For additional commands, e-mail: user-help@commons.apache.org
>>
>>
>>
>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
Rahul Akolkar wrote:
>
> On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>>
>> Well,
>> Can you please elaborate a bit more? My question is why should we reload
>> the
>> same classes multiple times for a jar file that is shared by multiple web
>> apps?
> <snip/>
>
> Generally you want your apps to be self-contained. The servlet
> specification talks about the web app and its directory structure,
> shared stuff is often container specific (I did mention portability).
>
>
> Well, from what I understand, at least in tomcat (which is what we use),
> there is a shared/lib
> directory for jars that are common across applications. These jars need
> not be container specific.
>
>
> And I am not sure what you mean portability? Could you explain a bit more?
>
>> Also, if I do not use digester, then this is not an issue - so what
>> are people who use digester doing (apart from duplicating war files)?
> <snap/>
>
> I think you mean duplicating libraries in war files for different web
> apps with similar application dependencies.
>
> I meant duplicating a jar file that is shared across applications in each
> of the applications's WEB-INF/lib
> directories. I would think that there should be a way to put them in
> shared/lib directory and still be able to use digester to construct them.
>
>
>> I do
>> not like the idea of duplicating same war files for each web app - so is
>> there a good reason to do that (apart from being a workaround for
>> problems
>> with digester.)
>>
> <snap/>
>
> I still think you mean adding the same jars to each WEB-INF/lib -- its
> portable and its safe.
>
> -Rahul
>
>
>>
>>
>> Rahul Akolkar wrote:
>>>
>>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>>
>>>> Can you please elaborate? Are you suggesting that I should just package
>>>> all
>>>> three jar files in WEB-INF/lib?
>>>>
>>> <snip/>
>>>
>>> If they are needed by the said web app, yes.
>>>
>>> -Rahul
>>>
>>>
>>>> Rahul Akolkar wrote:
>>>>>
>>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>>>
>>>>>> Hi
>>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>>> common- can be used by non web apps
>>>>>> webapp-common - common stuff shared by web apps.
>>>>>> my-webapp.jar - a particular web app.
>>>>>>
>>>>>> I am using digester to build my classes for the app my-webapp.jar.
>>>>>> In
>>>>>> the
>>>>>> digester rules, I have classes that are in all three jar files. Now,
>>>>>> ideally
>>>>>> speaking, I should be able to put the webapp-cmmon and common jar
>>>>>> files
>>>>>> in
>>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>>>> results
>>>>>> in the digester failing with "NoClassDefFoundException". The problem
>>>>>> goes
>>>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>>>> class
>>>>>> loader can see those classes. However, the common jar is already in
>>>>>> the
>>>>>> shared/lib being used by other apps. I added some new "common" stuff
>>>>>> for
>>>>>> the
>>>>>> my-webapp.jar and hence running into this issue.
>>>>>>
>>>>>> My latest thinking is to separate out the portion of the classes
>>>>>> being
>>>>>> used
>>>>>> by the my-webapp.jar from the common jar file into its own jar. Then
>>>>>> I
>>>>>> can
>>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>>>> retain
>>>>>> the common jar in the shared/lib. Is there a better approach? What is
>>>>>> the
>>>>>> best practice in this scenario. Does someone have an idea of overhead
>>>>>> in
>>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>>> instead
>>>>>> of
>>>>>> sharing them in common/lib? What I do not like about this issue is
>>>>>> that
>>>>>> I
>>>>>> think this issue would not be there if I was creating objects without
>>>>>> using
>>>>>> digester - so a way to use the approach (where I can access the
>>>>>> common
>>>>>> classes from digester) would be really ideal in my opinion.
>>>>>>
>>>>>> I did search the google and also this forum - I note that someone
>>>>>> suggested
>>>>>> to always bundle each jar files within the web app itself separately.
>>>>>> What
>>>>>> is the rationale for that?
>>>>>>
>>>>> <snip/>
>>>>>
>>>>> Portability, potential trouble with statics etc. Also, digester itself
>>>>> (and beanutils in particular) should never be shared.
>>>>>
>>>>> -Rahul
>>>>>
>
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>
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>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by Rahul Akolkar <ra...@gmail.com>.
On Sat, Jan 3, 2009 at 3:51 PM, rmenon <rm...@gmail.com> wrote:
>
> Well,
> Can you please elaborate a bit more? My question is why should we reload the
> same classes multiple times for a jar file that is shared by multiple web
> apps?
<snip/>
Generally you want your apps to be self-contained. The servlet
specification talks about the web app and its directory structure,
shared stuff is often container specific (I did mention portability).
> Also, if I do not use digester, then this is not an issue - so what
> are people who use digester doing (apart from duplicating war files)?
<snap/>
I think you mean duplicating libraries in war files for different web
apps with similar application dependencies.
> I do
> not like the idea of duplicating same war files for each web app - so is
> there a good reason to do that (apart from being a workaround for problems
> with digester.)
>
<snap/>
I still think you mean adding the same jars to each WEB-INF/lib -- its
portable and its safe.
-Rahul
>
>
> Rahul Akolkar wrote:
>>
>> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>>
>>> Can you please elaborate? Are you suggesting that I should just package
>>> all
>>> three jar files in WEB-INF/lib?
>>>
>> <snip/>
>>
>> If they are needed by the said web app, yes.
>>
>> -Rahul
>>
>>
>>> Rahul Akolkar wrote:
>>>>
>>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>>
>>>>> Hi
>>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>>> common- can be used by non web apps
>>>>> webapp-common - common stuff shared by web apps.
>>>>> my-webapp.jar - a particular web app.
>>>>>
>>>>> I am using digester to build my classes for the app my-webapp.jar. In
>>>>> the
>>>>> digester rules, I have classes that are in all three jar files. Now,
>>>>> ideally
>>>>> speaking, I should be able to put the webapp-cmmon and common jar files
>>>>> in
>>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>>> results
>>>>> in the digester failing with "NoClassDefFoundException". The problem
>>>>> goes
>>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>>> class
>>>>> loader can see those classes. However, the common jar is already in the
>>>>> shared/lib being used by other apps. I added some new "common" stuff
>>>>> for
>>>>> the
>>>>> my-webapp.jar and hence running into this issue.
>>>>>
>>>>> My latest thinking is to separate out the portion of the classes being
>>>>> used
>>>>> by the my-webapp.jar from the common jar file into its own jar. Then I
>>>>> can
>>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>>> retain
>>>>> the common jar in the shared/lib. Is there a better approach? What is
>>>>> the
>>>>> best practice in this scenario. Does someone have an idea of overhead
>>>>> in
>>>>> terms of performance etc if we "duplicate" jar files in each app
>>>>> instead
>>>>> of
>>>>> sharing them in common/lib? What I do not like about this issue is that
>>>>> I
>>>>> think this issue would not be there if I was creating objects without
>>>>> using
>>>>> digester - so a way to use the approach (where I can access the common
>>>>> classes from digester) would be really ideal in my opinion.
>>>>>
>>>>> I did search the google and also this forum - I note that someone
>>>>> suggested
>>>>> to always bundle each jar files within the web app itself separately.
>>>>> What
>>>>> is the rationale for that?
>>>>>
>>>> <snip/>
>>>>
>>>> Portability, potential trouble with statics etc. Also, digester itself
>>>> (and beanutils in particular) should never be shared.
>>>>
>>>> -Rahul
>>>>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
Well,
Can you please elaborate a bit more? My question is why should we reload the
same classes multiple times for a jar file that is shared by multiple web
apps? Also, if I do not use digester, then this is not an issue - so what
are people who use digester doing (apart from duplicating war files)? I do
not like the idea of duplicating same war files for each web app - so is
there a good reason to do that (apart from being a workaround for problems
with digester.)
Rahul Akolkar wrote:
>
> On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>>
>> Can you please elaborate? Are you suggesting that I should just package
>> all
>> three jar files in WEB-INF/lib?
>>
> <snip/>
>
> If they are needed by the said web app, yes.
>
> -Rahul
>
>
>> Rahul Akolkar wrote:
>>>
>>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>>
>>>> Hi
>>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>>> common- can be used by non web apps
>>>> webapp-common - common stuff shared by web apps.
>>>> my-webapp.jar - a particular web app.
>>>>
>>>> I am using digester to build my classes for the app my-webapp.jar. In
>>>> the
>>>> digester rules, I have classes that are in all three jar files. Now,
>>>> ideally
>>>> speaking, I should be able to put the webapp-cmmon and common jar files
>>>> in
>>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>>> results
>>>> in the digester failing with "NoClassDefFoundException". The problem
>>>> goes
>>>> away if we put all three jars in the WEB-INF/lib since the digester
>>>> class
>>>> loader can see those classes. However, the common jar is already in the
>>>> shared/lib being used by other apps. I added some new "common" stuff
>>>> for
>>>> the
>>>> my-webapp.jar and hence running into this issue.
>>>>
>>>> My latest thinking is to separate out the portion of the classes being
>>>> used
>>>> by the my-webapp.jar from the common jar file into its own jar. Then I
>>>> can
>>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>>> retain
>>>> the common jar in the shared/lib. Is there a better approach? What is
>>>> the
>>>> best practice in this scenario. Does someone have an idea of overhead
>>>> in
>>>> terms of performance etc if we "duplicate" jar files in each app
>>>> instead
>>>> of
>>>> sharing them in common/lib? What I do not like about this issue is that
>>>> I
>>>> think this issue would not be there if I was creating objects without
>>>> using
>>>> digester - so a way to use the approach (where I can access the common
>>>> classes from digester) would be really ideal in my opinion.
>>>>
>>>> I did search the google and also this forum - I note that someone
>>>> suggested
>>>> to always bundle each jar files within the web app itself separately.
>>>> What
>>>> is the rationale for that?
>>>>
>>> <snip/>
>>>
>>> Portability, potential trouble with statics etc. Also, digester itself
>>> (and beanutils in particular) should never be shared.
>>>
>>> -Rahul
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
>>> For additional commands, e-mail: user-help@commons.apache.org
>>>
>>>
>>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Digester-1.8-classloader-issue-when-using-tomcat-tp21268177p21269147.html
>> Sent from the Commons - User mailing list archive at Nabble.com.
>>
>>
>> ---------------------------------------------------------------------
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>>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by Rahul Akolkar <ra...@gmail.com>.
On Sat, Jan 3, 2009 at 3:44 PM, rmenon <rm...@gmail.com> wrote:
>
> Can you please elaborate? Are you suggesting that I should just package all
> three jar files in WEB-INF/lib?
>
<snip/>
If they are needed by the said web app, yes.
-Rahul
> Rahul Akolkar wrote:
>>
>> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>>
>>> Hi
>>> I have three jar files: common, webapp-common, my-webapp.jar.
>>> common- can be used by non web apps
>>> webapp-common - common stuff shared by web apps.
>>> my-webapp.jar - a particular web app.
>>>
>>> I am using digester to build my classes for the app my-webapp.jar. In
>>> the
>>> digester rules, I have classes that are in all three jar files. Now,
>>> ideally
>>> speaking, I should be able to put the webapp-cmmon and common jar files
>>> in
>>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>>> results
>>> in the digester failing with "NoClassDefFoundException". The problem goes
>>> away if we put all three jars in the WEB-INF/lib since the digester class
>>> loader can see those classes. However, the common jar is already in the
>>> shared/lib being used by other apps. I added some new "common" stuff for
>>> the
>>> my-webapp.jar and hence running into this issue.
>>>
>>> My latest thinking is to separate out the portion of the classes being
>>> used
>>> by the my-webapp.jar from the common jar file into its own jar. Then I
>>> can
>>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>>> retain
>>> the common jar in the shared/lib. Is there a better approach? What is the
>>> best practice in this scenario. Does someone have an idea of overhead in
>>> terms of performance etc if we "duplicate" jar files in each app instead
>>> of
>>> sharing them in common/lib? What I do not like about this issue is that I
>>> think this issue would not be there if I was creating objects without
>>> using
>>> digester - so a way to use the approach (where I can access the common
>>> classes from digester) would be really ideal in my opinion.
>>>
>>> I did search the google and also this forum - I note that someone
>>> suggested
>>> to always bundle each jar files within the web app itself separately.
>>> What
>>> is the rationale for that?
>>>
>> <snip/>
>>
>> Portability, potential trouble with statics etc. Also, digester itself
>> (and beanutils in particular) should never be shared.
>>
>> -Rahul
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
>> For additional commands, e-mail: user-help@commons.apache.org
>>
>>
>>
>
> --
> View this message in context: http://www.nabble.com/Digester-1.8-classloader-issue-when-using-tomcat-tp21268177p21269147.html
> Sent from the Commons - User mailing list archive at Nabble.com.
>
>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by rmenon <rm...@gmail.com>.
Can you please elaborate? Are you suggesting that I should just package all
three jar files in WEB-INF/lib?
Rahul Akolkar wrote:
>
> On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>>
>> Hi
>> I have three jar files: common, webapp-common, my-webapp.jar.
>> common- can be used by non web apps
>> webapp-common - common stuff shared by web apps.
>> my-webapp.jar - a particular web app.
>>
>> I am using digester to build my classes for the app my-webapp.jar. In
>> the
>> digester rules, I have classes that are in all three jar files. Now,
>> ideally
>> speaking, I should be able to put the webapp-cmmon and common jar files
>> in
>> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that
>> results
>> in the digester failing with "NoClassDefFoundException". The problem goes
>> away if we put all three jars in the WEB-INF/lib since the digester class
>> loader can see those classes. However, the common jar is already in the
>> shared/lib being used by other apps. I added some new "common" stuff for
>> the
>> my-webapp.jar and hence running into this issue.
>>
>> My latest thinking is to separate out the portion of the classes being
>> used
>> by the my-webapp.jar from the common jar file into its own jar. Then I
>> can
>> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and
>> retain
>> the common jar in the shared/lib. Is there a better approach? What is the
>> best practice in this scenario. Does someone have an idea of overhead in
>> terms of performance etc if we "duplicate" jar files in each app instead
>> of
>> sharing them in common/lib? What I do not like about this issue is that I
>> think this issue would not be there if I was creating objects without
>> using
>> digester - so a way to use the approach (where I can access the common
>> classes from digester) would be really ideal in my opinion.
>>
>> I did search the google and also this forum - I note that someone
>> suggested
>> to always bundle each jar files within the web app itself separately.
>> What
>> is the rationale for that?
>>
> <snip/>
>
> Portability, potential trouble with statics etc. Also, digester itself
> (and beanutils in particular) should never be shared.
>
> -Rahul
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
> For additional commands, e-mail: user-help@commons.apache.org
>
>
>
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Re: Digester 1.8 classloader issue when using tomcat
Posted by Rahul Akolkar <ra...@gmail.com>.
On Sat, Jan 3, 2009 at 2:14 PM, rmenon <rm...@gmail.com> wrote:
>
> Hi
> I have three jar files: common, webapp-common, my-webapp.jar.
> common- can be used by non web apps
> webapp-common - common stuff shared by web apps.
> my-webapp.jar - a particular web app.
>
> I am using digester to build my classes for the app my-webapp.jar. In the
> digester rules, I have classes that are in all three jar files. Now, ideally
> speaking, I should be able to put the webapp-cmmon and common jar files in
> the shared/lib and the my-webapp.jar in WEB-INF/lib. However, that results
> in the digester failing with "NoClassDefFoundException". The problem goes
> away if we put all three jars in the WEB-INF/lib since the digester class
> loader can see those classes. However, the common jar is already in the
> shared/lib being used by other apps. I added some new "common" stuff for the
> my-webapp.jar and hence running into this issue.
>
> My latest thinking is to separate out the portion of the classes being used
> by the my-webapp.jar from the common jar file into its own jar. Then I can
> bundle the webapp-common ahd my-webapp.jar in to the WEBINF/lib and retain
> the common jar in the shared/lib. Is there a better approach? What is the
> best practice in this scenario. Does someone have an idea of overhead in
> terms of performance etc if we "duplicate" jar files in each app instead of
> sharing them in common/lib? What I do not like about this issue is that I
> think this issue would not be there if I was creating objects without using
> digester - so a way to use the approach (where I can access the common
> classes from digester) would be really ideal in my opinion.
>
> I did search the google and also this forum - I note that someone suggested
> to always bundle each jar files within the web app itself separately. What
> is the rationale for that?
>
<snip/>
Portability, potential trouble with statics etc. Also, digester itself
(and beanutils in particular) should never be shared.
-Rahul
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