Ever stumbled across this?

javax.mail.SendFailedException: Sending failed;
   nested exception is:
      javax.mail.MessagingException: 501 5.0.0 HELO requires domain address

I wasn’t able for a long time to find the solution in the net although many people reported having this problem. The only hint you find is “There was an invalid entry in /etc/hosts”. But noone said exactly what the “invalid entry” was.

I myself found that there was no invalid entry but the configured hostname of the machine (issue “hostname” in a shell) cannot be resolved by DNS. The result is the given error message from the mail server.

What is happening? JavaMail resolves its own hostname by asking for the local hostname. The SMTP protocol requires the sending domain while handshaking. The server will try to resolve the domain by its DNS. If the hostname sent cannot be resolved then the server responds with “HELO requires domain address” as stated above.

I hope that this issue now becomes clearer to all of you.

PS: Solution is make sure your hostname can be resolved by DNS. Fix your hostname if it’s wrong or add the DNS entry.

Grrr, that was nasty. I upgraded my Ubuntu to 11.10 after the 11.04 installation on my Lenovo laptop did not boot anymore with the latest kernel update. I usually install all updates that Ubuntu’s Update Manager proposes and never had problems so far. Until yesterday when the last kernel update was received.

The laptop did not boot anymore. It halted somewhere without any further notice. Switching to the console with Ctrl-Alt-F1 and checking the X11 log at /var/log/Xorg.0.log revealed that NVIDIA graphics driver could not be loaded anymore. Re-installing the driver did not fix the problem . Well, at least I could boot the old kernel and check systems out.

However, I wasn’t able to make the newest kernel working with NVIDIA’s kernel module. So I finally tried the distribution upgrade to 11.10. But again, the system stuck in the boot. Even worse, I had a new symptom:

Unable to connect to the system bus: Failed to connect to socket /var/run/dbus/system_bus_socket: Connection refused

An internet research turned up this excellent forum thread which told me that the distribution upgrade had failed to migrate two directories. Following the instructions of #24 – using mv command and setting chmod 1777 /run/lock did finally help me to repair the system.

So guys, if you observe the weird behaviour after upgrading a kernel on an NVIDIA based computer, check out:

• The X11 log for messages about your kernel module
• Wiki page http://wiki.ubuntuusers.de/Grafikkarten/NVIDIA/nvidia
• Wiki page http://wiki.ubuntuusers.de/Grafikkarten/Nvidia
• and of course, google your boot log error

I am in time this year . The new DIY calendar is available – in English and German. Of course, the calendars differ from Ygor’s template in having week numbers on all templates.

I didn’t created a Windows executable that runs without any additional library. So you have to build the version from your own scratch. The source code is available at my Subversion repository.

I was lucky to test IceScrum, a french project, within our company. The test went quite well until we migrated to new Release 4. It seemed to be stable for a few hours. Then several users complained. They couldn’t login anymore. As an administrator I found out that the common reason for this is them missing Administrator role. By doing so, I could solve the problem.

However, several other problems stayed. Browsing projects wasn’t possible as well as browsing teams. Tasks could not be created anymore.

So here is my advice: Don’t upgrade yet to release 4. The release is an advance, definitely. But the bugs are too heavy to productively use it.

PS: Downgrading is a nightmare. Please, make a database backup before installing release 4. It will save you a lot of effort.

This maintenance release was awaited for quite a long time now. Due to some personal restrictions, I wasn’t able to publish it earlier. Version 2.2 doesn’t add any functionality but upgraded Apache’s POI library that can handle newer Excel versions.

You can download the new version here or visit the Homepage of the utility where you will find some examples on how to use it.

Many of you might use Oracle’s JNLP Download Servlet, delivered with JDK in jnlp-servlet.jar. One of the nice features of this servlet is the automatic replacement of variables at runtime, e.g. codebase and context. However, the existing documentation does not reveal all of these replacements. While searching for a solution where I need to put the server name into the JNLP file, I also examined the source code of JnlpDownloadServlet. And voilá: the feature is already there but not documented.

Here is the complete list of replacements that the servlet does for you while delivering a JNLP:

• $$name: will be replaced by the name of the URL file requested (without path, e.g. myfile.jnlp)
• $$hostname: will be replaced by the servername as given in the HTTP(S) request
• $$codebase: will be replaced by the codebase (request without URL file: http://my.server/appname/somedir/)
• $$site: will be replaced by the protocol, server and port, e.g. http://my.server:8080

I hope you’ll find that useful next time you look for a solution to deliver WAR files to individual servers with the specific servername in its JNLP file.

These two lines in /etc/default/grub let grub2 remember what system you booted last time and will automatically start this system when rebooting:

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

You need to update grub2 afterwards to have the new configuration activated:

update-grub

To all of you who don’t want to wait for the next releases of any of my projects there are good news. I introduced Nightly Builds now which are linked on individual project’s pages. In case you detect any missing build, just send me a message via the contact page.

I know, 2011 has already started a few weeks ago. However, I still owe you the DIY Planner calendar. Of course, the calendar differs from Ygor’s template in having week numbers on all templates. This year, I translated it to German as well, so you can have the German or the English version for download.

Unfortunately, I haven’t been able yet to create a Windows executable that runs without any additional library. So you have to build the version from your own scratch. The source code is available at my Subversion repository.

I finished this release some months ago but didn’t find time yet to finally release it. Version 2.1 introduces some new features and classes that ease handling of table-like data from different sources:

• New TableReader implementations for JDBC, XML, JTable
• New TableWriter implementations for HTML and XML
• Introduction of type conversion to allow object-string conversion and vice versa while reading and writing tables
• New Reader and Writer wrappers that read and write JavaBeans.
• New Filter implementations for TableReader that remove rows and columns.
• Some abstract classes were separated into general base classes and stream-handling classes. This allows easier development of non-stream based implementations.

You can download the new version here or visit the Homepage of the utility where you will find some examples on how to use it.