ActiveMQ 4.2 and IBM JRE 1.4

["David D. Lucas" <dd...@lse.com>]

First off, thanks to everyone who put together a great open source package
like ActiveMQ.  I am very impressed with it.  Great Job!!!

I am trying to deploy ActiveMQ 4.2 to WebSphere 5.1.  I was able to do
this with ActiveMQ 4.1, but with 4.2 I am seeing the "Unsupported
major.minor version 49.0" error.  I assume that the ActiveMQ classes or
something it is dependent on is compiled with JRE 1.5 byte code instead of
JRE 1.4.  My assumption, of course, is that 4.2 will continue to support
JRE 1.4 backward compatibility.  If this is not correct, can someone
document that or point me to the correct location?

While I am on the topic with WebSphere, is there a way to use the embedded
broker on multiple web containers all pointing to the same JDBC
persistence store?  I have yet to try this, but I would like all the
brokers to pull from the same persistent queue.  Is this possible?

Thanks in advance,
Dave

Re: ActiveMQ 4.2 and IBM JRE 1.4

["David D. Lucas" <dd...@lse.com>]

Not directly what my client was looking for, but might be the easiest way
to resolve their needs.   With the WAS 5.1 Generic JMS Provider, I can
easily configure the client side, but is there a way to create an instance
of the broker in the WebSphere container?  Like using a combination of
Spring and a WebContainer?   Or is there an old JCA 1.0 RAR laying around
that I could use to deploy in WAS 5.1? ;-)

I should probably move this to the users email list, but one last question.
Do you have a recommended approach in a tightly controlled firewall
environment to communicate between brokers?  Does ActiveMQ 4.1 support
HTTP between brokers?

Thanks again!
Dave

Re: ActiveMQ 4.2 and IBM JRE 1.4

[James Strachan <ja...@gmail.com>]

On 5/25/07, David D. Lucas <dd...@lse.com> wrote:
> Will consider our options.
> Thanks!

FWIW I just updated that page to mention another option is to have 1
database and each broker instance uses JDBC Master/Slave; then each
web app uses failover to connect to the one active broker. Then each
instance can come & go yet you only have 1 database.

http://activemq.apache.org/jdbc-master-slave.html

It has a similar effect (one DB, no single point of failure) just
implemented in a different way.
-- 
James
-------
http://macstrac.blogspot.com/

Re: ActiveMQ 4.2 and IBM JRE 1.4

["David D. Lucas" <dd...@lse.com>]

Will consider our options.
Thanks!
Dave

Re: ActiveMQ 4.2 and IBM JRE 1.4

[James Strachan <ja...@gmail.com>]

On 5/25/07, David D. Lucas <dd...@lse.com> wrote:
> Thanks for the quick response.  I will try the retrotranslator first.
>
> I did not explain my intent in the other question.
>
> I want the ability for each ActiveMQ "instance" to use the same database
> tables for persistence message store and retrieval.

Afraid not..
http://activemq.apache.org/can-two-brokers-share-the-same-database.html

-- 
James
-------
http://macstrac.blogspot.com/

Re: ActiveMQ 4.2 and IBM JRE 1.4

["David D. Lucas" <dd...@lse.com>]

Thanks for the quick response.  I will try the retrotranslator first.

I did not explain my intent in the other question.

I want the ability for each ActiveMQ "instance" to use the same database
tables for persistence message store and retrieval.  The question is can I
do that and have any persistent message appear to one or more of the other
brokers running on different containers assuming I put a message to the
same named queue?

I want to deploy the broker embedded to my web container and use the
database as a way to "distribute" messages.  Will the naming and locking
defined in the database persistent store mechanism allow multiple brokers
to point to that store and retrieve messages from it?

Is that more clear or foggier?  :-)

Thanks again,
Dave

Re: ActiveMQ 4.2 and IBM JRE 1.4

[James Strachan <ja...@gmail.com>]

On 5/25/07, David D. Lucas <dd...@lse.com> wrote:
> First off, thanks to everyone who put together a great open source package
> like ActiveMQ.  I am very impressed with it.  Great Job!!!
>
> I am trying to deploy ActiveMQ 4.2 to WebSphere 5.1.  I was able to do
> this with ActiveMQ 4.1, but with 4.2 I am seeing the "Unsupported
> major.minor version 49.0" error.  I assume that the ActiveMQ classes or
> something it is dependent on is compiled with JRE 1.5 byte code instead of
> JRE 1.4.  My assumption, of course, is that 4.2 will continue to support
> JRE 1.4 backward compatibility.  If this is not correct, can someone
> document that or point me to the correct location?

4.2 or later is built with Java 5 by default; since on Java 5 the new
concurrency code is faster & less buggy.

We may get around to creating a separate distro of retrotranslated
jars for 1.4. (Patches most welcome!:)

http://activemq.apache.org/contributing.html

Until then you can just install the retrotranslator JIT in your JVM to
auto-swizzle any Java 5 jars.
http://retrotranslator.sourceforge.net/#jit


> While I am on the topic with WebSphere, is there a way to use the embedded
> broker on multiple web containers all pointing to the same JDBC
> persistence store?

Just deploy one :)

The issue is from web apps they usually can't see the same broker via
VM transport. So either use TCP, or put the ActiveMQ jars in the
system class path.

-- 
James
-------
http://macstrac.blogspot.com/