Sharing common libraries and ejbs between multiple ears

Question

Hi
I have been going through various articles at O'Reilly and discussions at serverside
(some outdated) on the packaging options in J2EE.
http://www.onjava.com/pub/a/onjava/2001/06/26/ejb.html?page=2
http://www.onjava.com/pub/a/onjava/2001/07/25/ejb.html
http://www2.theserverside.com/home/thread.jsp?thread_id=7530
I am still undecided as to what is the best way to package and deploy
- a set of EJBs (Stateless Session beans) and
- utility libraries
that need to be shared by multiple ears.
We have a set of components - 4 session ejbs and 15 utility classes like log4java,
xerces, custom utilities etc... which need to be shared by all applications running
on the server (in a clustered environment).
There are over 22 applications and these will be packaged in individual ear files.
If we choose to put the common EJBs and utilities in each of the application's
ear, then for every change to this common library all the applications will need
to be repackaged and redeployed, which obviously is not desirable.
If we choose to use the 'Class-Path' option in manifest file, from what I understand
the path to be specified is a relative path within the ear i.e. the path cannot
point to archives outside the .ear file, which does not serve our purpose. Am
I right in this understanding?
What is the best way to package and deploy these common components under these
circumstances?
Has anybody tried something like this before?
Would appreciate your comments on this.
Thank you.

Answer 1

"Kumar" <[email protected]> wrote in message
news:[email protected]...
In My opinion,
I would be packaging the all utilities into a single jar file and be using
in the application server class path directly. whenever I want to change
this jar file I can change at one shot and package this jar file and keepit
in the classpath again. This works very well, if and only if each EAR file
is not using its own version of a libary of utility jar file. All earfiles
should be using a single and common library.In this case when you update the .jar file, you would have to restart the
server. I am not aware of any good solution which alleviates this.
>
If I include this utility jar file into all ear files, the following arethe
difficulties we need to handle in the future.
- What if utility library has been changed frequently, it leads to
re-package all .ears and re-deployment
- Unnecessarily adding a copy of a single jar file to all ear files,
increases complexity
- Any new application needed to be deployed, again which uses utility, we
need add the utility jar file to ear file
- There is no logical separation and simplicity
Thanks
Kumar
"Kiran P" <[email protected]> wrote in message
news:[email protected]...
Hi
I have been going through various articles at O'Reilly and discussions
at
serverside
(some outdated) on the packaging options in J2EE.
http://www.onjava.com/pub/a/onjava/2001/06/26/ejb.html?page=2
http://www.onjava.com/pub/a/onjava/2001/07/25/ejb.html
http://www2.theserverside.com/home/thread.jsp?thread_id=7530
I am still undecided as to what is the best way to package and deploy
- a set of EJBs (Stateless Session beans) and
- utility libraries
that need to be shared by multiple ears.
We have a set of components - 4 session ejbs and 15 utility classes likelog4java,
xerces, custom utilities etc... which need to be shared by allapplications running
on the server (in a clustered environment).
There are over 22 applications and these will be packaged in individualear files.
If we choose to put the common EJBs and utilities in each of theapplication's
ear, then for every change to this common library all the applicationswill need
to be repackaged and redeployed, which obviously is not desirable.
If we choose to use the 'Class-Path' option in manifest file, from what
I
understand
the path to be specified is a relative path within the ear i.e. the pathcannot
point to archives outside the .ear file, which does not serve our
purpose.
Am
I right in this understanding?
What is the best way to package and deploy these common components underthese
circumstances?
Has anybody tried something like this before?
Would appreciate your comments on this.
Thank you.