Freitag, 25. Januar 2008

Deploying BIRT WebViewerExample in Tomcat 5.5

When deploying the WebViewerExample of the BIRT runtime as documented, the viewer application didn't start correctly but gave a access denied ( /var/lib/tomcat5.5/webapps/birt-viewer/documents
, because it couldn't create the documents directory in it's installation directory.

Some googling showed that the problem was that in Debian/Ubuntu Tomcat is started using the java security manager. The solution given was to deactivate the security manager in /etc/init.d/tomcat5.5, but that didn't quite convince me. I simply granted the web application all permissions by appending to /etc/tomcat5.5/policy.d/50user.policy:

grant codeBase "file:${catalina.base}/webapps/birt-viewer/-" {

Freitag, 18. Januar 2008

Cleaning up packages

Installing software in Kubuntu is really simple. Just launch Adept Manager, select the package you want and install it. The software is then installed automatically, as are any additional packages it depends upon.

Unfortunately, when removing the software again, any dependent packages that were installed automatically are not removed (Synaptic in Ubuntu is more intelligent, I wonder when Kubuntu will catch up here).

Recently, I learned about sudo apt-get autoremove and deborphan for cleaning up those packages that are no longer needed.

Donnerstag, 17. Januar 2008

Multimedia Support in NoMachine NX

I've finally found out how to enable sound when logged in an NX session, so I can remotely log in to my desktop computer (referred to as server in the description below), start up Amarok and hear music over the network (so far I've only tried it at home with 100 MBit LAN, when I look at the network traffic I doubt it will work via WLAN, let alone DSL …):

  1. enable multimedia support for the NX session by clicking Configure … then going to the Services tab and activating the corresponding option, then log on to the server

  2. on the server, go to System settings > Sound system > Hardware and select the Enlightened Sound Daemon (ESD) (I've translated the german text back to english, I don't know if it actually corresponds to an english Kubuntu)

  3. go to System settings > Notifications > Replay settings … and select KDE sound system; now playing a sound for a notification should already work!

  4. Start Amarok and go to Settings > Configure Amarok … > Audio output and select esd as output module; if it's not available, you must sudo apt-get install libxine1-gnome (I know, it looks like a strange package for Kubuntu/Amarok, but it contains the ESD output plugin for xine, Amarok's audio backend)

Now play some music in Amarok, you should hear it on the client where you started the NX session!

One more thing, it seems not to work when Amarok is automatically started when logging in (i.e. it was running when you logged out last time), in that case I quit Amarok, then log off from the NX session and start a new NX session.

Donnerstag, 3. Januar 2008

Adding JDBC driver in BIRT

I'm currently learning how to use BIRT, the open source Eclipse-based reporting system. After working through the tutorial I tried to add my own database, and so had to provide a JDBC driver for it. There are installation instructions on how to do it, but when testing the connection I always received Cannot load JDBC Driver class: org.sqlite.JDBC.

Only later I found a section in the online help where it says that the driver must be copied to a certain plugin directory first (/eclipse/plugins/

I've created an enhancement request for the installation instructions.

Update 2008-01-17: Obviously, it's not a bug but the effect of installing Eclipse in /opt with root ownership, and then starting Eclipse as a normal user.