Top 50: Interview with Joe Walker of the Direct Web Remoting Project Blog

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    Editor's note: In this interview, Community Manager Marla Parker continues her series of interviews with leaders of some of the most active projects on In this installment, she corresponds with Joe Walker of Direct Web Remoting, or DWR, a popular library for developing Ajax appliciations in Java, and one which we've highlighted in several feature articles (seeresources for links).

    What's DWR?

    Q: How would you describe your project, in a nutshell?

    A: DWR is the glue for Java and Ajax. It enables you to call Java classes on the web-server from Javascript in the browser, and in its latest release, to call Javascript functions in browsers on your website, from Java on the server. It comes with a DHTML library to help manipulate pages with data from the server.

    Q: Who is using DWR and what are they doing with it?

    A: Walmart are using DWR for their web store. CondeNast (owners of Reddit) are using DWR for several of their new startups like and Atlassian are using DWR for JIRA and Confluence and most things they do, including their cool new search engine. New York City is using it for their version of Google Maps. It's in Jive forums, and Recently it's been added to the Pebble weblogging tool, and it's in many other projects. I lose track.

    Working on DWR

    Q: What made you decide to start this project?

    A: I was responsible for in-sourcing an externally developed project that had huge design-level security holes. I'd just been working on a project that had lots of configuration files, and I wanted to make the system simpler. DWR was the result.

    Q: Is working on DWR part of your day job?

    A: Currently it is, part time - TIBCO have been sponsoring DWR development for the past 6 months. They've helped me and the DWR community considerably.

    Q: A popular open source project is a lot of work; what keeps you going?

    A: I think, it's the same as for most open source developers; a simple desire to control everything in the known universe. We're currently on schedule for world domination in 2 years time. Plus I've got this bad itch on my left shoulder. I'm hoping to add features to DWR so it can be used to fix that too.

    DWR on

    Q: What would you like to see added to the project section?

    A: With one exception I'd like to see less, not more. The one exception is conversion from CVS to SVN that project owners don't have to pay for. Aside for that major gripe, most of the features that we need are there, but could be more usable. My favorite example is the "How do I ... Get release notes for CollabNet 4.5.2?" link that is on virtually all project pages within To be honest I'm not interested in the release notes, so I doubt any of DWR's users are.

    Author's note: the details about this problem and what is available for fee or free are now available in the user generated FAQ under "Q. How do I convert my project from CVS to Subversion?"

    Q: Do you know how many users you have? and of your project members, how many of them contribute to DWR?

    A: I have no idea how many users DWR has. I do know it is being adopted very quickly by how often the DTD files are read. I blogged about it a few months ago, and the usage is still increasing.

    Q: How do you manage community member contributions?

    A: It depends a lot on what the contribution is. If it affects the core of DWR, I vet it closely and make sure I understand it. The further away from the core it gets, the less worried I am that changes will break things.

    Challenges and Surprises

    Q: Why did you chose the Apache License?

    A: Because ASF is the best way to drive adoption in the Java world.

    Q: What has been your most difficult challenge?

    A: Reverse Ajax, as described in a blog about that very question.

    Q: What has been your biggest surprise?

    A: How little running a successful open source project is about development. Project management is a far bigger task

    Editor's note: We'd like to thank Joe for discussing DWR in this interview. You can look for more interviews with prominent project leaders in the coming weeks and months.