July 21, 2005

OSGi BoF at ApacheCon

Yesterday evening we had a BoF session at ApacheCon about OSGi.

OSGi is getting hot at Apache. Cocoon decided a few weeks ago to go that route to finally implement "real blocks" which have been our goal for more than 2 years. The directory project is considering using it and Alex Karasulu invited the Oscar project to join the ASF. And we see other projects interested in using OSGi as well such as James.

Why is it hot? It the service container landscape, OSGi fits inbetween heavyweight J2EE servers and ligtweight containers such as Excalibur, Spring or Pico. It provides among other things classloader isolation and hot deployment or remote application blocks (called "bundles").

There have been numerous attempts at writing such a container at Apache, either in Avalon (Fortress, Merlin) or Cocoon (the "kernel") but this always ended up to be either one-man shows or leading to fights about the container specification. This is what caused the death of the Avalon project. OSGi brings a solution to these social problems as it is developed elsewhere. We can't fight on the container specification, as it's already there. We just have to use it. And up to now, it happens to fulfill Cocoon needs and goals quite nicely.

Also, most projects needing such kind of container don't have the time nor willingness to write their own. OSGi has several implementations (both commercial and OSS) that are solid and stable and can be used right now.

One of the problems raised during the initial discussions about having Oscar joining the ASF were licence issues, as the R3 specification (the current version) doesn't have a real licence. Now Eclipse 3.1 heavily uses OSGi for its plugin architecture, using some features that will be in the upcoming R4 specification. And they happen to have already solved this issue, as the R4 API code will be released under the EPL.

So things seem to evolve quite nicely!

Posted by Sylvain Wallez at July 21, 2005 11:42 AM

This page says Oscar has a BSD license. So, you can use it as you like in whatever Apache licensed project.
It won't be the first ObjectWeb project to be used in an Apache project. The license of 2 ObjectWeb projects (ASM and JOTM) to enable cooperation between ObjectWeb and Apache communities (see this post, this another one about cooperation and this BOF Session during ApacheCon US 2004). Note also that HOWL is currently integrated in Apache Geronimo.
So, Oscar could be another basis for the ObjectWeb/Apache cooperation. I hope so.

Posted by: Dominique De Vito on July 23, 2005 01:13 PM

Oscar has a BSD license : see http://solutions.objectweb.org/

ASM => http://asm.objectweb.org/

JOTM => http://jotm.objectweb.org/

ObjectWeb/Apache cooperation => http://www.objectweb.org/phorum/read.php?f=25&i=49&t=49

and http://www.theserverside.com/discussions/thread.tss?thread_id=22542

BOF session about cooperation => http://apachecon.com/html/session-popup.html/e=MjAwNC9VUw?id=1154

HOWL => http://howl.objectweb.org/

Posted by: Dominique De Vito on July 23, 2005 01:17 PM

Dominique, I am aware of the cooperation efforts going on between OW and the ASF. This time it's different though, and there are no licence issues: Oscar *is* moving to the ASF.

Looks like the main goal of this is to attract more developpers to the project.

Posted by: Sylvain Wallez on July 23, 2005 10:10 PM

Sylvain, the way you put things is a little disapointing. Sounds like Apache is doing some shopping at ObjectWeb and takes whatever they like as in a supermarket. This lacks courtesy to say the least.

In addition, I'm not aware that ObjectWeb projects be allowed to be removed from under the ObjectWeb umbrella without a formal decision from the board. And I'm not aware of any board decision at OW regarding OSCAR.

- François

Posted by: F.Letellier on July 25, 2005 10:44 AM

Sorry for the wording François, it should have been "Oscar's primary developer will be leading a new incubating OSGi project at Apache": http://mail-archive.objectweb.org/oscar/2005-07/msg00030.html

Apache is in no way shopping at ObjectWeb. It just happens that Richard S. Hall thinks it is "a good way to raise OSGi awareness at a critical time in Java history", and hopes it "helps to continue to grow [the Oscar] community".

Now it happens that the new project is named Oscar and that OW's current code base will be the starting point of this project: http://mail-archives.apache.org/mod_mbox/incubator-oscar-dev/200507.mbox/%3C42E1579E.9030006@ungoverned.org%3E

Posted by: Sylvain Wallez on July 25, 2005 11:13 AM

Yes, I would say that the word "moving" is not exactly correct, since I don't plan on uprooting Oscar 1.0.x from ObjectWeb, I just plan to do my future development at Apache.

The original blog entry attests to the interest in OSGi at Apache, some of which is a direct result of announcing an Apache OSGi project. This type of synergy for OSGi is currently not present within ObjectWeb and if the only way to get it is to start an Apache OSGi project, then so be it.

My main agenda, since 2000, is to promote OSGi as an enabling technology for building modular and extensible Java applications and to promote research around it.

I believe this brings me closer to those goals.

-> richard

Posted by: Richard S. Hall on July 25, 2005 06:12 PM