Hi, We're OSGi. We mean no harm

Dear James,
I read your interesting interview with eWeek. There were many parts where we agreed, but I was also slightly puzzled with your observations about OSGi. "OSGi is this thing that kind of came from a different universe that's being used for modularity." I do agree that many people see the quality of the OSGi specs as out this world, but that seems a bit exagerated. I do agree we did not start out in the enterprise application space, we started in embedded world where space and performance constraints are pervasive, but after all I thought we both lived in the Java universe. However, this seems at odds with your remarks like "So we needed something that was a lot lighter weight." and "... OSGi's just too much fat."

Hmm, the OSGi core API is 27 classes. That is a all. Security, Module layer, Life cycle layer, and Service Layer. Exceptions, permissions, and interfaces. And one of them is even deprecated! Just the module layer in Jigsaw seems to have more classes, and they just got started ... Or did you mean the implementations? With Concierge at around 80k for an R3 implementation and Felix at 350k it seems a stretch to call us fat? OSGi is even deployed in smart cards.

It's true, our documentation is a bit fat. The core is described in 300 pages. Though we have lots of pictures! And we have virtually no errata, despite the fact that OSGi has been used in tens of thousands of applications over the last decade.

I'd like to tell you a little anecdote. In 1997 I tried to convince Ralph Johnson about Java. My key argument was that Java was so nicely small and therefore easy to understand. Only 11 packages! Ralph, a famous Smalltalker, looked at me wearily and said: "Just wait." Oh boy, was he right. That lesson still drives me every day to keep OSGi lean and mean, annoying many people along the way, but I guess that is the price one needs to pay.

If you think project Jigsaw will be leaner than OSGi, well, modularity is a problem where size does matter. You cannot demonstrate modularity with a Hello World because modularity solves the problem of large evolving code bases. [deleted]

So, James, I think that are lots of details where we did not get it perfect, but OSGi's weight is not one of them. The misconceptions about OSGi at Sun stand to cost our industry a lot of money and pain in the coming years. Project Jigsaw's simplicity is a fallacy, hidden by the fact that they do not address the hard issues that OSGi has now been working on for over a decade. All major application servers are today based on OSGi, not because it was fun or a hype, but because they had no choice. These are applications in themselves that have a scale where modularity is not an option but a necessity. The success of open source will move many Enterprise applications in this same realm.

If you believe that a simplistic solution can address the needed scale, well than indeed we do live in another universe. However, please remember that we're here as friends, to help, and mean no harm.

Your's sincerely,

Peter Kriens