Development Java Linux Red Hat Software

jpackages error: Missing Dependency: /usr/bin/rebuild-security-providers

Jpackages on Red Hat has a nifty bug that causes dependency errors.

Luckily, somebody has created a fix as a rpm package 🙂

rpm -ivh jpackage-utils-compat-el5-0.0.1-1.noarch.rpm

And then jpackages works.

Linux Software

ImportError: No module named trac

When working with a new Trac installation you can bump into the error message “ImportError: No module named trac”. This is usually caused by Trac installation not unzipping all the needed files.

The following one liner should fix the issue:

cd /usr/lib/python2.4/site-packages;unzip Trac-0.12.2-py2.4.egg
Linux Red Hat

package subversion-1.6.12-0.1.el5.rf.x86_64 (which is newer than subversion-1.4.2-4.el5_3.1.i386) is already installed

Package conflict that can appear some times, a simple fix then is to downgrade first, then upgrade:


yum --downgrade update subversion
yum update subversion

Tips for implementing a custom JAAS login module for Jetty

1) jetty-web.xml

You can gather all specific settings for Jetty in the file WEB-INF/jetty-web.xml, remember to also specify paths for the role principals if you use your own classes for that.

Example jetty-web.xml file:

<!-- Jetty specific config file -->

<!-- Tell jetty where to find login config -->
<Call name="setProperty">

<!-- Bug fix for Jetty to properly handle login config in a per-project setup -->
<Set name="serverClasses">
	<Array type="java.lang.String">

<!-- Create login realm -->
<Get name="securityHandler">
	<Set name="userRealm">
			<Set name="name">*NAME OF YOUR REALM*</Set>
			<Set name="LoginModuleName">*NAME OF YOUR LOGIN CLASS*</Set>
			<Set name="roleClassNames">
				<Array type="java.lang.String">

2) Adding roles to a user in commit

When you want to give a user roles(like admin, moderator etc), you can add those to the user when he or she is authenticated and commit is called upon:

	public boolean commit() throws LoginException {
		MyUserPrincipal user = new MyUserPrincipal("username");

		//Add logged in user as first principal

		//Add roles for the logged in user
		subject.getPrincipals().add( new MyGroupPrincipal("admin") );
		subject.getPrincipals().add( new MyGroupPrincipal("moderator") );
Twitter Web

List of people twittering about Libya

Blog post last updated 16:04 GMT, 23.february 2010

This is a manually updated list of people twittering about the clashes that have now spread to Libya

Note: please comment if you miss anybody/anything here.

Twitter accounts updated within the last hour:
feb17voices, tweets about ti
alihabibi1, tweets about it
F_albinali, tweets about it
BBC World news, tweets about it
AJEnglish, tweets about it
Jnoubiyeh, tweets about it

Twitter accounts updated within the last three hours:

Twitter accounts updated later:



Debugging GWT: Did you forget to inherit a required module?

You will receive this error if you are using classes in your GWT project that GWT does not have access to. Make sure that you have added something like this in your gwt.xml file, within your module element:

    <source path="" />
Software Windows

Acer machine with Windows XP giving reboot after booting

Today i had a problem with a Acer machine that kept rebooting just after the machine had started up Windows, typically a couple of seconds after everything was loaded. After managing to disable auto-reboot upon crash, i got a hold of the error message 0x00000050 (aka PAGE_FAULT_IN_NONPAGED_AREA ). After testing a “crash report analyzer” i noticed that the cupit was ”elock2fsctldriver.sys”, which comes from Acer`s eLock software.

So i booted into Windows Safe Mode, uninstalled the program, and then the machine rebooted without any issues. 🙂

(This was of course after testing all the hardware and drivers, which is normally the problem…)