Wednesday Dec 12, 2007

GlassFish @ Bangalore, Chennai and Pune - Metro, jMaki & JRuby

I presented on GlassFish and other related technologies (Metro, jMaki and JRuby) in Bangalore, Chennai and Pune last week. The slides used during the preso are here. And here is the list of questions (along with answers) for you:

  1. What does WSIT offer ?

    WSIT stands for Web Services Interoperability Technology. It is a component of Metro - the Web services stack in GlassFish. WSIT specifically provides support for Security, Reliability, Transactions and interoperability with .NET 3.0. A number of screencasts are available to get you started with Metro and enable all the enterprise features mentioned using NetBeans IDE.
  2. Is Metro plugin available for NetBeans version < 6.0 ?

    Yes, Metro plugin is available for NetBeans 5.5.1. This is clearly explained in screencast #ws4. NetBeans 6.0 is now released and is the recommended version of the IDE.

  3. How do I use LDAP for authentication while using Metro based web service (with Security Token Service) interoperating with .NET web service?

    Security Token Service (STS) can be configured for LDAP authentication. STS service end can be protected with Sun Java System Access Manager web service agent (JSR 196 plugin). It can validate and authenticate the incoming user name token (username / password) against configured LDAP store at STS service side (when Access Manager is hosted as STS) and then issue the corresponding SAML token. You could also write AuthenticationValidator plugin to STS service, that can access and validate incoming username / password against Access Manager LDAP store using Access Manager Client SDK.
  4. Do Metro support Kerberos?

    Metro 1.0 does not support Kerberos. However the latest nightly builds of Metro provide Kerberos support.
  5. I want to contribute to GlassFish. Which areas can I contribute?

    Yes, GlassFish is 100% open source and encourage committers. Some of the ideas are available here. Please feel free to suggest any contributions at
  6. What Ruby features are getting into Java language?

    If Java closures proposal is accepted then that will be a Ruby feature.
  7. Does jMaki take care of browsing history ?

    jMaki does not support browser history yet but this feature will be made available as an extension in the near future.
  8. Is jMaki extensible ?

    Yes, read how jMaki framework can be extended as explained here.
  9. What is the performance impact of using jMaki ?

    jMaki.js is the initialization script (18kb) for jMaki that is loaded when the web application is loaded. This script provides multiple features, included but not limited to:
    • support for common event model between widgets from multiple toolkits (using publish/subscribe)
    • Dynamic Container at component level - allows to resize the component within <div> and iframe
    • doAjax call (allows to asynchronously invoke services from back end)
    • JSON.serialize (serializes JavaScript objects to JSON)
    • inspect (2-level deep inspection of object)
    • logger & debugging (log all publish/subscribe events and other messages to enable debugging)
    • namespace API  (allows to namespace all the widgets for clean separation)

    The jMaki wrapper is a minimal code that needs to be written anyway to invoke the code anyway so there is no additional overhead there.

  10. Is Comet supported in GlassFish/jMaki?

    Yes, read about Comet support in GlassFish The Grizzly Comet and Writing a Comet application using GlassFish. Also try a simple sample that demonstrates how jMaki and Comet (read the explanation) work nicely with each other.

  11. Can GlassFish deploy EJB 2.0 apps ?

    GlassFish is Java EE 5 compliant which maintains backwards compatibility with J2EE 1.4 and so EJB 2.0 applications can be deployed.

  12. Do GlassFish support Active and Passive cluster ?

    In GlassFish the cluster instances talk to each other for health monitoring through GMS (of Shoal). The buddy instances talk to each other for replication of the session state. When a failure is detected the LoadBalancer can failover the request to any instance in the cluster. The session in question will be fetched from a replica to this instance in order to continue the conversational state of the session. In this sense, we have an active cluster.

    GlassFish does not have a concept of a standby or passive cluster which will take over when an active cluster fails altogether. That is usually considered a high cost approach for redundancy and not advisable. 

    Read more discussion here.

  13. Can we add a Metro Web service wrapper be created around EJB 2.0 ?

    Nope, Metro Web service wrapper can be created around EJB 3.0 only.

  14. How can an application deployed on WebLogic be migrated to GlassFish ?

    Migrate2GlassFish helps automate the migration of J2EE/Java EE applications to GlassFish.

  15. Can Entity beans be configured only as read-only beans - caching server for these beans ?

    Yes, read about the characteristics, good practices, how to deploy and refresh read-only beans.

  16. How can jMaki applications run behind the firewall ?

    Add the following Servlet parameters to web.xml:


    This is described in detail at

Technorati: conf webservices web2.0 ruby jruby projecmetro glassfish netbeans q&a


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Arun Gupta is a technology enthusiast, a passionate runner, author, and a community guy who works for Oracle Corp.

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