OSGi standards and adoption

The TSS thread on Virgo and whether or not OSGi is ready for mainstream enterprise application development contains some misconceptions.

Firstly, that SpringSource is somehow not involved in the OSGi standards process.

That couldn't be further from the truth. Recently we've led the standardisation of Spring DM into the blueprint service specification and reference implementation while IBM provided the compliance tests. We are developing the reference implementation of the OSGi web container while IBM wrote the specification and are providing the compliance tests. Then, as we look to the future, we are leading two, and involved in other, new specifications targeted at R4.3.

Secondly, it is easy to get the impression that other vendors, such as IBM and Oracle, are about to solve the adoption problem.

I certainly hope they do, but, at least in the case of IBM's WebSphere Application Server OSGi alpha, their programming models seem very similar to that of dm Server and their development and build tools, where the real adoption issues seem to be, do not seem to be particularly advanced.

Perhaps IBM's large customer base and marketing machine will encourage developers to jump the necessary hurdles. But the tricky thing about a product like WAS is that, after the alpha code has been rolled into the main product, it will be very hard to measure real usage. The only real evidence will be customer testimonials and APAR (i.e. external defect) rates against the OSGi features, which IBM typically do not publish.

Let's see how Virgo gets on. At least the adoption should be easier to measure as users will almost certainly be using it for its OSGi features.

WebSphere OSGi Application Model

As noted previously, WebSphere Application Server's alpha support for OSGi applications is similar to that of SpringSource dm Server. Now IBM's open source server, Geronimo, has taken its first steps to join the party.

Apparently Geronimo 3.0 is now based on OSGi, like all other modern Java app servers. (I wonder what vestigial traces of its GBean/XBean heritage remain?)

Geronimo's OSGi application model is provided by the Aries incubator, so I wonder if that is also the base of the WAS alpha, since Geronimo is essentially WAS CE.

Maybe the answer is that the closed source WAS is also based on Aries, but I didn't dare accept the license agreement on the download to find out.

SpringSource dm Server catching on

The recently announced alpha driver of IBM WebSphere Application Server v7 support for OSGi applications is covered in a brief dzone interview with Kirk Knoernschild of the Burton Group.

As Kirk notes in his blog, SpringSource dm Server has already brought OSGi to the enterprise. dm Server v1.0 shipped in September 2008 and v2.0 will enter RC1 in the next few weeks.

The WAS alpha has some features in common with dm Server, notably repositories and applications along similar lines to plans and PARs. Immitation is the sincerest form of flattery or, putting it another way, IBM has validated dm Server's approach.

I'm still waiting for technical details of WebLogic DM Server, but since it is microkernel based (unlike WAS) and with a name like that, it's likely to validate dm Server further.

Meanwhile GlassFish and JBoss support for OSGi is coming along nicely, so it'll be fascinating to see what kind of OSGi application models these projects end up providing.