javax.jmdns.impl.tasks.Prober run
WARNING: run() exception
java.io.IOException: Operation not permitted
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:625)
at javax.jmdns.impl.JmDNSImpl.send(JmDNSImpl.java:1200)
at javax.jmdns.impl.tasks.Prober.run(Prober.java:163)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)

And when you access hudson in browser, it stays with the message “Please wait while Hudson is getting ready to work….” forever.

Initially I thought the problem might be because the ports which are required by the Hudson server i.e. 8080 and 5353, were not opened in the Firewall. I opened those, but the error remained.

After googling for sometime, I could find similar issues being reported here:

http://issues.hudson-ci.org/browse/HUDSON-7129?page=com.atlassian.streams.streams-jira-plugin:activity-stream-issue-tab

And the issue got fixed by adding

-Dhudson.DNSMultiCast.disabled=true

to the java command as follows:

java -Dhudson.DNSMultiCast.disabled=true -jar hudson.war --httpPort=8080

We first looked at RadiantCMS, with the intention of building our web application on top of it. But then decided to instead build our web app from scratch and then make parts of it editable using Comatose [which is a "MicroCMS"]. This way, we have more flexibility to add features to the web app using the Rails API and available plugins, rather than being constrained by RadiantCMS system.

Things we liked about Comatose:

• Its implemented as a Rails plugin – which makes it a breeze to install
• Implementing Single Sign On is also simple. Because it works well with the  restful_authentication plugin.
• Comatose allows rendering of pages inline from your application view – just like rendering a partial in a Rails app. To include an “editable” tool tip within a form, something as simple as the following is enough:

  • <%= render :comatose=>'about' %>

There’s of course a lot more you can do with this plugin. Check it out.

Now for the bad part

• The main issue is font inconsistency. There are some options for setting the font size, but they don’t work as expected – because the CSS styles are inherited from our app.
• In production mode, there is a noticeable delay between making changes in the CMS and the updated content showing up on the main site. Not sure why this is the case.

1. Export the certificate from IE by following the instructions given here: http://www.tech-pro.net/export-to-pfx.html
2. The certificate with Private key will be exported as PFX format in the above step – but this cannot be used by the jarsigner. So you need to convert it into “p12 format” which the jarsigner can understand. For that you need to use Mozilla. First import the certificate  saved in step 1 into Mozilla as follows:
   1. From the “Edit” menu select “Preferences” and open the “Privacy & Security” category and click on the “Certificates” item.
   2. In the “Manage Certificates” section, click on the “Manage Certificates” button.
   3. In the “Certificate Manager” window, the “Your Certificates” tab should automatically open. (If not, select it.)
   4. Click the “Impor”t button at the bottom of the window.
   5. It prompts you to select an existing file; select your certificate file from the location where you saved it in when you exported it.
   6. It prompts you to provide the “Master Password”; enter it, if you have set one.
   7. It prompts you to provide the password used to encrypt the certificate backup; enter it.
   8. It should say “Successfully restored your certificate(s) and private key(s).” Click OK.
3. Then export the certificate as p12 format:
   1. From the “Edit” menu select “Preferences” and open the “Privacy & Security” category and click on the “Certificates” item
   2. In the “Manage Certificates” section, click on the “Manage Certificates” button.
   3. In the “Certificate Manager” window, the “Your Certificates” tab should automatically open. (If not, select it.)
   4. To export your “DOEGrids” or “KCA Personal Certificate”, click on it to select it, and click the “Backup” button at the bottom of the window.
   5. You’ll be prompted to specify a filename and location for the “PKCS#12-format” certificate file (file extension will be “.p12″ in UNIX/Linux,  ”.pfx” in Windows).  Provide them and click OK.
   6. A dialog box requesting the Master Password may appear (the password and certificate database). If you have set a Master Password, provide it. If not, you can make one up and provide it (optional). Remember this password!
   7. You’ll be prompted to make up and (twice) enter a second password. This one is for restoring this particular backup of this certificate. Remember this password!
   8. Once the system says it’s successfully backed up your certificate and private key, click OK.
4. We also need to know the alias of the “.p12″ file so run:

    keytool -list -storetype pkcs12 -keystore <path to the cert file>

5. Then you will see output like this:

Keystore type: pkcs12 Keystore provider: SunJSSE

Your keystore contains 1 entry

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx, Apr 26, 2006, keyEntry,

Certificate fingerprint (MD5):hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh:hh

The xxxx-xxx… number is the alias for the key

6. Change your ant script as follows to sign the certificate:

<target name="signjar" depends="jar">
 <signjar jar="yourJar.jar" storetype="pkcs12"
   keystore="yourkey.p12" alias="Your Alias"
   storepass="your password"/>
</target>

JQT is a family of JQuery plugins comprising of the most common widgets used in “modern” sites.  We’ve used quite a few of the widgets on our sites in the last 3-4 projects and it  has certainly helped us improve the look and feel of these sites – with much less effort that what would have been required otherwise.

Installing and using JQT on your site is also super simple.  Download a JS file of ~6kb and include in your web page.  The documentation and demos provided for each widget is excellent – so you should be on your way to actually getting stuff done very quickly after the download.

Bottom line – you’ve got pretty much no excuse, to not check it out .

1. We want to reuse application code built for a .NET application
2. We want to integrate the DLLs with a Java based sever technology
3. Should be simple enough to maintain the code by .NET professionals

There are couple of Java-COM bridging solutions I came across.

• Java Native Interface (JNI)
• JACOB
• Scriptom (Groovy – COM Scripting)
• Java Native Access (JNA)
• JNBridge

In this post, we’ll see how Scriptom can be used to access DLLs.

Scriptom is a module in Groovy (A Java VM based scripting language) which wraps the JACOB classes to make it more usable. Scriptom’s syntax looks like VB.NET code.

Lets jump in to the sample application.

Assume that we have a VB class named TimerState in the TestDLL VB.NET project, exposes the COM, signed and generates the DLLs.

Following is the TimerState VB class. In this class, we have an event UpdateTime which raises an event when to notify updated time.

 <Microsoft.VisualBasic.ComClass()> Public Class TimerState

    Public Event UpdateTime(ByVal Jump As Double)

    Public Sub TimerTask(ByVal Duration As Double)
        Dim Start As Double
        Dim Second As Double
        Dim SoFar As Double

        Start = Timer
        SoFar = Start
        Do While Timer < Start + Duration
            If Timer - SoFar >= 0.1 Then
                SoFar = SoFar + 0.1
                RaiseEvent UpdateTime(Timer - Start)
            End If
        Loop
    End Sub
End Class

We want to use this logic in the Scriptom code and do something whenever a UpdateTime event is raised. Here are the steps:

1. Register the DLLs (this is required step for the Java Virtual Machine to get meta data about the DLLs)
2. Download Scriptom
3. Copy the jacob-*.dll to any system PATH
4. Have all the JARS from Scriptom jar folder available in the CLASSPATH

Following is the sample code for invoking

import org.codehaus.groovy.scriptom.ActiveXObject // Imports the ActiveX object class which holds the reference to the class in DLL

def timer = new ActiveXObject("TestDLL.TimerState") // Looks for the meta data in the registry with "TestDLL.TimerState" name and creates a reference to that class

def time = 1.00

timer.events.UpdateTime = { variants -> // event registration for UpdateTime event in the VB class. Variants holds the data passed from the event. In this case, it is Jump value.
    println "UpdateTime: " + variants[0] // We're just printing the upated time
}

timer.TimerTask(time) // starting the timer task in TimerState class
while(true) { // keeping itself alive to respond when timer events are raised
}

In the next post, we’ll discuss about JNBridge, a comercial solution.