• From a technical point of view I didn’t like the user interface. There are too many ways of doing the same. Just take a simple feature like posting a picture… You can post it on a wall, or post it into your pictures and then reference this post from your own wall or a wall of someone else. It is just not implemented well.
• There is a prvacy and traceability aspect. I don’t want my customers to search for facts about me. The facts are mine and I want to control who knows them and who is not supposed to know. Facebook is not a platform I trust my facts, since it is designed to share my private facts with other parties.
• I was bored by poor, brainless, first-idea-came-in-mind posts. I just want to read something with substance, and in 99,999% of Facebook posts there was no substance.
• I hated the notifications and messages. I switched off all email notifications. Even not notified by email, the messages are collected and stored in your personal Facebook inbox. In general, the way notification works in Facebook is very similar to a message sent to wrong mailing list. Did it already happened in your company that you receive a incorrectly sent message and then continue to receive the “I don’t understand….” and “Remove me from the mailing list…” messages several hours, since people send those to the entire mailing list again? In particular, I don’t like broadcast-broadcast mode of communication, since it work only in cases in which all participants write the same and have the same opinion. I believe, that in such case the communication is not required anymore…
• I don’t like the word “Friend” or at least how Facebook define it. In the beginning, there is a collecting phase – people tend to add everyone to the “Friend” list – a classmate, a former co-worker, the wife of a former co-worker which had a red dress on the last corporate event – in general people you don’t know. This list also contains some real Friends – people you spend time with. After some time and tons of spam delivered from people you don’t know you may decide to go to the shrinking phase – delete all the people that are not real friends. On the other hand, you don’t need Facebook to be connected to your friends, but you need it to be connected to those people, who are not your friends! Especially you possibly would be interested in recovering a friendship with someone from the high school if you find out that the person goes to the same parties or concerts as you do. (In fact you again don’t need Facebook for that). So my last phase was anti-friend. I deleted all but my classmates, since I don’t have much contact with them and Facebook was the only way to stay connected. In doing so I ended up in having a Friend list of people I don’t really know anymore.
• People tend to post more stupid things on Facebook than the post over other channels. It is a paradox, but pretty serious “Friends” post a complete nonsense, which is not a problem in general. The problem is that 100 other “Friends” instantly vote for that nonsense. I really think that this is a problem and this problem is a part of the system Facebook. You are just one click away from liking something, but a whole post away from a dislike. This seems to be a general feature of Facebook and an extreme effective way to distribute nonsense.
• And last, but not least, people who use computers only for emailing and Facebook underestimate the privacy feature. They post over their entire life there, spending an incredible amount of time on scrolling through those nonsense messages of others and hitting the like button or leaving a stupid comment. It is addictive, and yes, I know at least five people who should go to a specialist with that problem.

In my opinion, the technology as art should move us forward. You may call me conservative, old-fashioned or just stupid, but there should be some aim in all that communication, picture sharing and messaging. Facebook doesn’t provide this aim – it is a social network for its own (Just compare it to some social network with an aim, like linked.in, FlickR or Xing is).

And finally no, there is no “like” button under this post – just a comment field, empty and waiting for your idea…
(Image taken from here).

In comparison to other Sun Certifications, this one is not focusing on a test of how good you learn the API of a JEE Specification. The theory questions aim to test a general understanding of the JEE technologies, their usage areas and their purpose. There are also some questions testing your understanding of the advantages and caveats of JEE Stack. In general it was not very difficult – I spend several days on preparation and got my 89% (you only need 57% to pass).

The assignment part is pretty interesting. You have to submit a document describing the architecture of the system under development, which contains a set of UML 2 diagrams (class, sequence, deployment, use case). This part is a good excersize for any architect. In addition, you have to identify the main three threats and describe mitigation strategies for them. I found this part interesting, since I noticed that I’m usually not doing it on such level of detail, but judge about the risks based on my own experience. The second and the third parts are evaluated together. You can get at most 160 points and need 114 to pass (71%). I spend almost a week every evening for creation of the assignment and was happy of getting 140 point (87%).

You are among the elite 1% of certified Java professionals who have gone on to achieve the Java Enterprise Architect certification.”

That’s really funny.

At any rate, I enjoyed the preparation time, the exams and I’m glad about the result.

Bei der Einführung von Serviceorientierten Architekturen (SOAs) ist Wiederverwendung nur eines von vielen Zielen, die miteinander um Priorität konkurrieren. Wiederverwendung erreicht man also keinesfalls allein durch die Wahl einer entsprechenden technischen Platt form, sondern nur in Verbindung mit vielen Entscheidungen auf organisatorischer Ebene. In diesem Artikel wollen wir die aus unseren Erfahrungen wichtigsten Vorgehensweisen und Erfolgsfaktoren beschreiben, die bei der Erreichung einer hohen Wiederverwendung innerhalb einer SOA kritisch oder hilfreich sind.

The main idea of the BlackBeltFactory is to create an e-learning platform around computer engineering skills. The site provides so-called courses and workshops: real educational content to different subjects. In order to access the course material, you not only need the account at the site, but should also have a coach, helping you to consume the material. If you get one (I’ll tell you later how this works), you can study the content and solve excersises. On any questions you can contact the coach who is intended to help you, usually via skype or email.

Once you are done with studying – you should test yourself by registering to an exam. An exam is a set of online multiple-choice questions. In order to pass exams, you also require some contribution points. You get contribution points for any kind of community activity: connect you status update with twitter, edit questions, post comments, translate course materials – everything you do for the site and community gives you contribution points. In addition, you can create groups and invite people into them.

Every passed exam gives you some knowlegde points. For a number of knowlegde points earned, you get a belt. Belts have different colors: white, yellow, orange, green, blue, brown and finally black. For the black belt you not only need enough knowlegde points, but also have to be a successful coach for two other students, which means that they have to pass the exams and give you feedback.

After you get a blackbelt, you may offer coaching for money. You give 20$ + 15% of the coaching proce to BlackBeltFactory, but I suppose this is fair enough. The site gives you a possibility to create coaching offers (free or paid) and manage the students, who are looking for the coaches – a real e-learning marketplace.

I had an idea to get the black belt by passing exams of subject I think I’m expert in, without taking all the courses. It turned out, that the exam questions are pretty good – you easily pass the subject you are good in, but you ultimatively fail in subjects where you have knowledge gaps. Another problem you face is the lack of contribution points. For this purpose, there exist a so-called belt track, a series of exams in which passing an exam enables the next one without spending contribution points. The exams are predefined but cover basic Java, OO, XML and Web technolgoies, so I could use the track to achieve the blackbelt quickly.

I like the site because I have the possibility to test my knowledge. The tests are not trivial, but reveales subjects you should deepen. On the other hand the site lives from the contributions. You can do anything – from commenting bad exam question to designing new questions, exams, courses – whatever. I also liked the education part, where you have to teach a Java fundamental course for free. That’s not trivial if a person you teach really starts from scratch, but very interesting and challenging. I also like the fact that you can do a lot without paying money – very good business model.

Sometimes, the site shows strange behaviour, but you can ever finish your work. At some places the site seems to be not following its own styleguide and look&feel, but these are details. I’m a big fan of BlackBeltFactory.

Martin told about the OSGi technology and the usage of it in big projects. He advertised the OSGi module system but also pointed on some pitfalls during design of the architecture. I was a little dissapointed, since it was a kind of entry-level talk, and its main emphasis was to recollect the importance of the service-oriented principle during system design. He pointed out the importance of loosly coupling and implicit dependency which foster maintainability of the system for many years. In the same time the fulfillment ofsuch architectural principles does not come for free.

Jan Köhnlein made a talk on DSLs in general and Xtext 2.0 in particular. The guys from itemis did a nice job in developing Xbase, a new language which can be used inside of the user DSL. For me, it is a huge step towards ubiquitous application of DSLs in software projects. Xbase give the ability to specify behaviour inside of DSLs. It is statically typed, compiles to Java, supports closures and type inference, operator overloading, etc.. – many nice features to use a little more functional programming language features in your DSL. Especially the ability to mix Java Types with Types defined in your DSL in combination with higher-order functions seems very powerfull to me.

Finally, Ralf Ebert made a very decent presentation on Git – the popular distributed versioning system. I am a big fan of Git and use it for many things i develop and saw many different presentation on those – but Ralf’s was the best one. He explained very plastically the difference in usage of Git to other versioning systems like SVN or CVS. He also showed a nice demo by showing some interesting branching and merging scenarios by switching between two users (Alice and Bob) on his machine and developing a simple web application. It was fast, precise and understandable – very nice talk.

The next Nordic Coding is planned for the August 19th, 2011.

More pictures in my FlickR set…

Please contribute to this incredible project!

I played with Bugzilla for the site I hosted for TLA+ but I wanted to try something new and installed JIRA on my home server. The nice story about it is: it is written in Java and it costs only 10$. I installed the bundled (which includes Tomcat) version on my old home server and used my MySQL DB for bugs.

Switching the database

After the default installation I changed the following Datasource configuration to switch from HSQL-DB to MySQL in conf/server.xml:

<Resource name="jdbc/JiraDS"
  auth="Container"
  type="javax.sql.DataSource"
  driverClassName="com.mysql.jdbc.Driver"
  url="jdbc:mysql://localhost/jira?autoReconnect=true
&amp;useUnicode=true&amp;characterEncoding=UTF8"
  username="user"
  password="secret"
  maxActive="20"
  validationQuery="select 1"
/>

And changed the dialect in atlassian-jira/WEB-INF/classes/entityengine.xml:

<datasource name="defaultDS" field-type-name="mysql"
  helper-class="org.ofbiz.core.entity.GenericHelperDAO"
  check-on-start="true"
  use-foreign-keys="false"
  use-foreign-key-indices="false"
  check-fks-on-start="false"
  check-fk-indices-on-start="false"
  add-missing-on-start="true" check-indices-on-start="true">
    <jndi-jdbc jndi-server-name="default"
      jndi-name="java:comp/env/jdbc/JiraDS"
    />
</datasource>

Integrating with Apache Webserver

In addition, I don’t like entering ports into the browser, so I activated mod_jk Apache module and shifted the JIRA tomcats ports 50000 upwards:

<Connector port="58080" protocol="HTTP/1.1"
  maxHttpHeaderSize="58192"
  maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
  useBodyEncodingForURI="true" enableLookups="false"
  redirectPort="58443"
  acceptCount="100" connectionTimeout="20000"
  disableUploadTimeout="true"/>
    <Context path="/jira/"
    docBase="${catalina.home}/atlassian-jira"
    reloadable="false">
    ...
</Connector>
<Connector port="58009"
  enableLookups="false"
  redirectPort="58443"
  protocol="AJP/1.3" />

Please note that also I changed the path to “/jira/”. So in order to access it from the browser, you need to type http://server:58080/jira/
In Apache HTTPD Server configuration, I loaded the mod_jk module and configured a worker for JIRA:

# Where to find rkers.properties
# Update this path to match your conf directory location
# (put workers.properties next to httpd.conf)
JkWorkersFile /etc/apache2/workers.properties

# Where to put jk shared memory
# Update this path to match your local state directory or logs directory
JkShmFile     /var/lock/apache2/mod_jk.shm

# Where to put jk logs
# Update this path to match your logs directory location
# (put mod_jk.log next to access_log)
JkLogFile     /var/log/mod_jk.log

# Set the jk log level [debug/error/info]
JkLogLevel    error

# Select the timestamp log format
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "

#Mounts
JkMount /jira/* jira

The worker.properties file defines a worker using the Tomcat AJP13 connector:

#workers using ajp13
worker.list=jira

# Set properties for jira (ajp13)
worker.jira.type=ajp13
worker.jira.host=localhost
worker.jira.port=58009

Let it mail

For maximum comfort I tried to let my JIRA installation send me mails using my GMail mail account. I followed the instruction on the JIRA page.

<Resource name="mail/GmailSmtpServer"
  auth="Container"
  type="javax.mail.Session"
  mail.smtp.host="smtp.googlemail.com"
  mail.smtp.port="465"
  mail.smtp.auth="true"
  mail.smtp.user="myusername@gmail.com"
  password="mypass"
  mail.debug="true"
  mail.smtp.starttls.enable="true"
  mail.smtp.socketFactory.class="javax.net.ssl.SSLSocketFactory"
/>

I finished the setup and got the following error:

com.atlassian.mail.MailException: javax.mail.MessagingException:
  Exception reading response; nested exception is:
        javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
        at com.atlassian.mail.server.impl.SMTPMailServerImpl.send(SMTPMailServerImpl.java:191)
        at com.atlassian.mail.queue.SingleMailQueueItem.send(SingleMailQueueItem.java:47)
        at com.atlassian.mail.queue.MailQueueImpl.sendBuffer(MailQueueImpl.java:68)
        at com.atlassian.jira.service.services.mail.MailQueueService.run(MailQueueService.java:23)
        at com.atlassian.jira.service.JiraServiceContainerImpl.run(JiraServiceContainerImpl.java:67)
        at com.atlassian.jira.service.ServiceRunner.execute(ServiceRunner.java:48)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:191)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:516)

The problem results from the fact, that GMail uses TLS certificates which has to be imported as described here. After executing the steps, my JIRA mails me on changes of the Issue states…

After all, I can create my issues and should focus on the home improvement again. But now I’m very well organized.

The Screen

In order to view the beautiful pictures delivered from the source, you need a TV set. In my childhood we had a monochrome Cathode Ray Tube (CRT) TV set, a huge box, incredible heavy, full of electrical components. Produced in Russia, its handle broke and we had nippers near the TV set in order to switch the channels (they were switched by rotating the handle). The next TV set we had could reproduce color but had approximately 12″ screen size. Its channels could be switched using small buttons. In the nineties, the time of big CRTs begun. A normal person could effort a 30″ CRT and of course it had a remote control. I saw my first plasma screen on an exhibition in Germany – I was thrilled by its relative small depth in comparison to a CRT. But the plasma screens of the nineties were heavy, consumed about 400W and had about 8 fans, which were pretty loud. Finally, the time of LCDs began and now the technology seem to be one of the main technologies in the market of TV sets. It is difficult to find a store selling CRTs in Germany.
A LCD screen has several parameters. Some of them are just attempts of vendors to deliver technology to the market before it is really ready. A good example of this is contrast ratio: in fact no sane person want to know what contrast ratio is delivered by the TV screen, it should be just enough. Other parameters are saying something about the quality of the picture you can see e.g. the resolution of the screen. The resolution of 1920 x 1080 pixels is the most common resolution of current Full HD (1080p) TV screens.

Source of Recorded Video

After everyone bought hundreds of movies on the Video Home System (VHS) cassetes, the industry changed the technology from a tape to a disc. The Digital Versatile Disc (DVD) killed the VHS during a decade in order to be killed by the new standard called Blue Ray Disc (BD). To explain the difference in one sentence: DVD delivers only PAL quality (576p, or 576 lines), BD delivers 1080p (1080 lines). A remarkeable difference, but not all movies profit from a higher quality. So take a chance to buy old movies, where the higher resolution doesn’t play a role on DVD, before you have to pay for an expensive BD.

Source of Broadcasted Video

In addition to high quality recorded video source, you can receve a broadcast program. In old days, the television broadcast was analog. Since two years, the analog broadcast is being scaled back in Germany and is being replaced by the Digital Video Broadcast-Terrestical standard (DVB-T). Current DVB-T standard is not designed to deliver HDTV, but eventually it will be replaced by DVB-T2. There are two other ways to deliver the video program: cable or satellite. The corresponding standards are called DVB-S (for Satellite) and DVB-C (Cable). Both standards can deliver digital pictures in HDTV (1080p). Most offers of channels in HDTV are encoded and not free. Still, there is a reason for fees that every German having a TV set has to pay: the public channels ARD and ZDF will be transmitted in HDTV starting in 2010, arte broadcasts the HDTV already, since the middle of 2008.

The Sound

In order to complete the high-quality cinema-like felling in the living room, the sound system should support something like 5.1 dolby surround. This inlcludes a set of four boxes, a center loudspeaker, a subwoofer and an dolby-surround amplifier.

Conclusion

I watched a wonderful movie on arte tonight. The beautiful pictures deliverd by a Full HD 1080p screen and the nice music from processed by the complex logic of the digital amplifier. It was Charlie Chaplins’ “Modern Times”, created by his genious in 1936 in USA: a restored black-white silent movie. A real masterpiece…