Grails and Linux on PowerPC with IBM's j9 JVM.

[kate rhodes]

The following was put together by my coworker, Porter. Hopefully it
will be useful to any other poor  geek sadled with deploying a grails
app to J9 (dear gods why?!?!)

And no, we weren't privy to the details of how java got installed on
this [expletive deleted] PPC IBM Blade server. Actually the hardware
is fine it's just the insanity of deploying java webapps to a non-Sun
JVM which you have todo because Sun's Java won't run under PPC Linux.

- kate = masukomi
http://weblog.masukomi.org/


Deployment Notes for Grails and Fedora Linux on PowerPC with IBM's j9 JVM.

So I have some notes on what was needed in terms of configuration to
get a Grails based application running on j9 -

1>  Grails uses Groovy a Java based Dynamic Language.  In order for it
to function under j9 the class loader verifier needs to be turned off
using the following option when starting the JVM.  -Xverify:none  This
can be added to the tomcat5.conf file - so that when the web server
starts up, the JVM is started with the option.

2>  Our app was originally configured to use a different mail server
than the standard mail server for the IES data center.  Accessing the
application - signing up with a new user produced a GPF error.
Although all the round-tip accesses to the database were successful -
the last step in completing the signup is the sending of a
confirmation/reminder email to the user.  Due to the inabilty to
access the mail server, j9 threw an extremely interesting error
message.

3>  Because our app uses the SMTP protocol to send mail there is the
possibility for a conflict concerning the mail transport
implementation installed under Linux.  In the environment on Tomcat8 -
j9 also had the Gnu Classpath Java APIs in the Classpath.  Although
the Grails application was deployed with a mail.jar and activation.jar
from Sun, in execution it finds the Gnu mail API first.  Apparently
the Gnu mail API is not 100% compatible with the Sun Java Mail API
specification.

In all cases the error received when these things aren't set is
extremely cryptic.  In the first case the system throws a ClassLoader
error indicating that a class is not found.  Looking into the .WAR
file being deployed shows that the class in question is in place;
it's caused by the dynamic nature of Grails/Groovy wherein class
behaviour is spliced in dynamically to the Model and Controller
classes.  In the second case j9 throws a GPF Fault - and does it's
version of a Core Dump.  Perusing the dump file doesn't seem to help -
as there is no indication of the class or method which caused GPF.
GPF is short for General Protection Fault - which means that something
is attempting to access a resource to which they do not have
permission (per the underlying operating system).  And finally once
past the GPF mail wouldn't send due to some incompatiblity with the
Gnu JavaMail API and the Sun specification JavaMail API.  Once the Gnu
mail.jar was replaced with the Sun version - email functioned
normally.

Luckily Google works well - but even then it took a lot of research
and trial and error to determine the root cause and what would fix the
problem.

Searching on these problems reveals Grails is by no means alone in
these issues - Eclipse has similar issues in some cases running on top
of j9 (and they're both products from IBM - at least initially).
JBoss - another large open source project that produced the first open
source EJB server also has had similar issues - and Apache Geronimo.

Just thought I should share the hard-won knowlege of some odd issues
in deploying to j9 - so that nobody else has to scratch their head and
wonder why something isn't working when it should "just run".

- Porter

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[Dierk König]

cool. that is worth putting on the wiki.

Dierk

> -----Original Message-----
> From: kate rhodes [mailto:[hidden email]]
> Sent: Donnerstag, 5. April 2007 0:07
> To: [hidden email]
> Subject: [grails-user] Grails and Linux on PowerPC with IBM's j9 JVM.
>
>
> The following was put together by my coworker, Porter. Hopefully it
> will be useful to any other poor  geek sadled with deploying a grails
> app to J9 (dear gods why?!?!)
>
> And no, we weren't privy to the details of how java got installed on
> this [expletive deleted] PPC IBM Blade server. Actually the hardware
> is fine it's just the insanity of deploying java webapps to a non-Sun
> JVM which you have todo because Sun's Java won't run under PPC Linux.
>
> - kate = masukomi
> http://weblog.masukomi.org/
>
>
> Deployment Notes for Grails and Fedora Linux on PowerPC with IBM's j9 JVM.
>
> So I have some notes on what was needed in terms of configuration to
> get a Grails based application running on j9 -
>
> 1>  Grails uses Groovy a Java based Dynamic Language.  In order for it
> to function under j9 the class loader verifier needs to be turned off
> using the following option when starting the JVM.  -Xverify:none  This
> can be added to the tomcat5.conf file - so that when the web server
> starts up, the JVM is started with the option.
>
> 2>  Our app was originally configured to use a different mail server
> than the standard mail server for the IES data center.  Accessing the
> application - signing up with a new user produced a GPF error.
> Although all the round-tip accesses to the database were successful -
> the last step in completing the signup is the sending of a
> confirmation/reminder email to the user.  Due to the inabilty to
> access the mail server, j9 threw an extremely interesting error
> message.
>
> 3>  Because our app uses the SMTP protocol to send mail there is the
> possibility for a conflict concerning the mail transport
> implementation installed under Linux.  In the environment on Tomcat8 -
> j9 also had the Gnu Classpath Java APIs in the Classpath.  Although
> the Grails application was deployed with a mail.jar and activation.jar
> from Sun, in execution it finds the Gnu mail API first.  Apparently
> the Gnu mail API is not 100% compatible with the Sun Java Mail API
> specification.
>
> In all cases the error received when these things aren't set is
> extremely cryptic.  In the first case the system throws a ClassLoader
> error indicating that a class is not found.  Looking into the .WAR
> file being deployed shows that the class in question is in place;
> it's caused by the dynamic nature of Grails/Groovy wherein class
> behaviour is spliced in dynamically to the Model and Controller
> classes.  In the second case j9 throws a GPF Fault - and does it's
> version of a Core Dump.  Perusing the dump file doesn't seem to help -
> as there is no indication of the class or method which caused GPF.
> GPF is short for General Protection Fault - which means that something
> is attempting to access a resource to which they do not have
> permission (per the underlying operating system).  And finally once
> past the GPF mail wouldn't send due to some incompatiblity with the
> Gnu JavaMail API and the Sun specification JavaMail API.  Once the Gnu
> mail.jar was replaced with the Sun version - email functioned
> normally.
>
> Luckily Google works well - but even then it took a lot of research
> and trial and error to determine the root cause and what would fix the
> problem.
>
> Searching on these problems reveals Grails is by no means alone in
> these issues - Eclipse has similar issues in some cases running on top
> of j9 (and they're both products from IBM - at least initially).
> JBoss - another large open source project that produced the first open
> source EJB server also has had similar issues - and Apache Geronimo.
>
> Just thought I should share the hard-won knowlege of some odd issues
> in deploying to j9 - so that nobody else has to scratch their head and
> wonder why something isn't working when it should "just run".
>
> - Porter
>
> ---------------------------------------------------------------------
> To unsubscribe from this list please visit:
>
>     http://xircles.codehaus.org/manage_email

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[Barry Lagerweij]

Hi Kate,

A few weeks ago, I've added some remarks to the Grails FAQ on running Grails on WebSphere (also on IBM's JVM). I encountered several interesting issues, your first issue is present in the FAQ, the classloading issue regarding mail.jar is not, although I did encounter similar issues with ant.jar.

Perhaps you could add the issues with Tomcat and mail.jar to the Grails FAQ ?

With kind regards,

Barry

On 4/5/07, kate rhodes <[hidden email]> wrote:

The following was put together by my coworker, Porter. Hopefully it
will be useful to any other poor  geek sadled with deploying a grails
app to J9 (dear gods why?!?!)

And no, we weren't privy to the details of how java got installed on
this [expletive deleted] PPC IBM Blade server. Actually the hardware
is fine it's just the insanity of deploying java webapps to a non-Sun
JVM which you have todo because Sun's Java won't run under PPC Linux.

- kate = masukomi
http://weblog.masukomi.org/


Deployment Notes for Grails and Fedora Linux on PowerPC with IBM's j9 JVM.

So I have some notes on what was needed in terms of configuration to
get a Grails based application running on j9 -

1>  Grails uses Groovy a Java based Dynamic Language.  In order for it
to function under j9 the class loader verifier needs to be turned off
using the following option when starting the JVM.  -Xverify:none  This
can be added to the tomcat5.conf file - so that when the web server
starts up, the JVM is started with the option.

2>  Our app was originally configured to use a different mail server
than the standard mail server for the IES data center.  Accessing the
application - signing up with a new user produced a GPF error.
Although all the round-tip accesses to the database were successful -
the last step in completing the signup is the sending of a
confirmation/reminder email to the user.  Due to the inabilty to
access the mail server, j9 threw an extremely interesting error
message.

3>  Because our app uses the SMTP protocol to send mail there is the
possibility for a conflict concerning the mail transport
implementation installed under Linux.  In the environment on Tomcat8 -
j9 also had the Gnu Classpath Java APIs in the Classpath.  Although
the Grails application was deployed with a mail.jar and activation.jar
from Sun, in execution it finds the Gnu mail API first.  Apparently
the Gnu mail API is not 100% compatible with the Sun Java Mail API
specification.

In all cases the error received when these things aren't set is
extremely cryptic.  In the first case the system throws a ClassLoader
error indicating that a class is not found.  Looking into the .WAR
file being deployed shows that the class in question is in place;
it's caused by the dynamic nature of Grails/Groovy wherein class
behaviour is spliced in dynamically to the Model and Controller
classes.  In the second case j9 throws a GPF Fault - and does it's
version of a Core Dump.  Perusing the dump file doesn't seem to help -
as there is no indication of the class or method which caused GPF.
GPF is short for General Protection Fault - which means that something
is attempting to access a resource to which they do not have
permission (per the underlying operating system).  And finally once
past the GPF mail wouldn't send due to some incompatiblity with the
Gnu JavaMail API and the Sun specification JavaMail API.  Once the Gnu
mail.jar was replaced with the Sun version - email functioned
normally.

Luckily Google works well - but even then it took a lot of research
and trial and error to determine the root cause and what would fix the
problem.

Searching on these problems reveals Grails is by no means alone in
these issues - Eclipse has similar issues in some cases running on top
of j9 (and they're both products from IBM - at least initially).
JBoss - another large open source project that produced the first open
source EJB server also has had similar issues - and Apache Geronimo.

Just thought I should share the hard-won knowlege of some odd issues
in deploying to j9 - so that nobody else has to scratch their head and
wonder why something isn't working when it should "just run".

- Porter

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[kate rhodes]

added J9 info to wiki.


--
- kate = masukomi
http://weblog.masukomi.org/

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