“Fun” with JavaWS and PAC (Proxy AutoConfig)

20. Oktober 2014

Using a *.pac / *.dat file for proxy auto-configuration is a very useful thing, especially in enterprise environments. Generally, JavaWS supports using PAC. But sadly, Oracle’s current JRE versions (7u71 / 7u72) refuse to use a PAC file that makes use of of JavaScript functions like dnsDomainIs(). Using such a PAC file will lead to errors like this:

javax.script.ScriptException: sun.org.mozilla.javascript.internal.EcmaError: TypeError: Cannot find function dnsResolve in object com.sun.deploy.net.proxy.SunAutoProxyHandler@e04204. (<Unknown source>#34) in <Unknown source> at line number 34

Caused by: sun.org.mozilla.javascript.internal.EcmaError: TypeError: Cannot find function dnsResolve in object com.sun.deploy.net.proxy.SunAutoProxyHandler@e04204. (<Unknown source>#34)

This looks like JDK-8038986 and JDK-6945158. So, it seems to be fixed in current version of OpenJDK, and hopefully, it gets fixed in Oracle’s JRE’s, too. In the meanwhile, the workaround found at JDK-6945158 worked for me, too: make sure that the PAC file returns anything without using dnsDomainIs(), for example using a Regex-based test like shExpMatch (thanks os!) or doing a simple string comparison like

if (host==”[hostname]“)
return “PROXY proxy_host:proxy_port”;

Linux Mint: wrong keyboard layout on login screen

10. Juni 2014

Mint users using a non-default keyboard layout (german, french and so on) may encounter an annoying bug regarding the Mint login screen: setting a locale won’t affect the keyboard layout. As result, you can’t login using a password that contains special characters. Logging in using the console still works fine.

So, the first obvious workaround is changing to a console (using ALT-CTRL-F1, for example), logging in and changing the password to another one which doesn’t contain special characters. But this is deprecated since using special characters are an important part of creating strong passwords.

To solve the issue, do the following: open the following file using your preferred text editor:

/etc/mdm/Init/Default

Go to the last line – it should be

exit 0

Insert a new line before that last line and enter

/usr/bin/setxkbmap de

for a german localisation. Choose the localisation according your needs, for example fr for french and so on.

Don’t forget to adapt the file again after upgrading to a new Mint version.

SSH-Tunnel für HTTPS-Access

18. Mai 2014
ssh -f <user>@<host> -L <localport>:<remoteserver>:443 -N

Nicht vergessen, URL mit https:// anzugeben.

Some Java NG Plugin / Applet resources

20. Juli 2012

Collection of some resources on the NG Java Plugin and new Applet features:

R-griffen :)

26. Februar 2012

Das Linux Magazin bringt in seiner Ausgabe 3/2012 einen – wie üblich sehr interessanten und auch für R-Anfänger wie mich geeigneten – Artikel zur grafischen Darstellung statistischer Daten mittels ggplot2 und R. Beim Testen der Beispiele stellte sich zwar schnell heraus, dass ggplot2 eine neuere Version von R voraussetzt – die bei Ubuntu Lucid (aktuelle LTS-Version) mitgelieferten Pakete etwa sind leider zu alt zur Installation von ggplot2. Das CRAN bietet aber auch für Lucid die nötigen Pakete.

Die read.csv()-Funktion warf bei mir zudem eine Fehlermeldung, es seien doppelte Zeilennamen vorhanden. Offenbar wird die erste Datenspalte (“Algorithmus”) als Quelle der Zeilennamen verwendet, und die Spalte enthält ja tatsächlich doppelte Werte. Abhilfe brachte das explizite Deaktivieren der Zeilennamen mit row.names=NULL.

Bei der Suche nach einer Hilfe zur Installation und Nutzung von R unter Lucid bin ich noch über einen prima Hinweis gestoßen: mit JGR gibt es ein ebenso einfaches wie hilfreiches GUI für R, das zB schön anzeigt, welche Argumente eine Funktion erwartet. Ausgestattet mit aktuelleren debs aus dem CRAN und „bewaffnet“ mit JGR steht der weiteren Erkundung Rs nichts mehr entgegen.

"Fun" with Funambol….

25. Januar 2012

Sadly there seem to be no “official” Funambol add-ons for newer Thunderbird versions. No matter using official or inofficial add-ons (for example those provided by memotoo.com), debugging strange errors isn’t really fun. For example the nice message “Error: code 2054″ when trying to sync a new client:

funamvol error code 2054

The log files don’t offer any more information. Searching the web doesn’t help, either, but the error seems to be caused by an SSL issue. In fact, i tried to access a (custom) Funambol server using https, and the SSL certificate was cacert based. Ok, but i’ve imported cacert’s root and class3 certs into Thunderbird’s cert cache already? Finally, i realized that the Funambol add-on just ignored the certs in the Thunderbird cert store and solely checked the root certificates provided by windows! After importing cacert’s root certificate in the windows cert store (take care to choose the right “department” – you have to manually select “trusted root certification authority” – or “Vertrauenswürdige Stammzertifizierungsstellen” in german…), everything worked like a charm.

PDF/A using FreePDF

1. Januar 2012

To create PDF/A-1b documents using FreePDF, just create a new profile (or modify an existing one) and add the following Ghostscript options to “Other Ghostscript Options” („Andere Ghostscript-Optionen“):

-dPDFA -dUseCIEColor -sProcessColorModel=DeviceCMYK

An additional PDFA_def.ps file isn’t required (in contrary to manually creating a PDF/A using “gs -dPDFA -dBATCH -dNOPAUSE -dNOOUTERSAVE -dUseCIEColor -sProcessColorModel=DeviceCMYK -sDEVICE=pdfwrite -sOutputFile=out-a.pdf PDFA_def.ps input.ps“).

With version 9.04, there’s a bug concerning the DocumentID generation that’s already fixed in trunk. So, until version 9.05 is out, a manual build ghostscript is required to benefit from the bugfix.

Fix undefined local variable or method `version_requirements’

9. Februar 2011

Fix ./script/../config/../vendor/rails/railties/lib/rails/gem_dependency.rb:99:in `requirement': undefined local variable or method `version_requirements’ for # (NameError):http://www.redmine.org/issues/7516

Transform ‘text’ numbers into numerical values in openoffice.org calc

30. November 2010

When pasting data into a Openoffice.org Calc Spreadsheet, it may happen that numerical values have been inserted as text values, so arithmetic operations on that values will fail or lead to unexpected results. To transform those numerical values into “plain” numbers, i recently found a message board thread proposing a simple search/replace using regex: using the search pattern

^.*$

and the replacement pattern

&

should do the trick.

Blog client /editor for blogger.com / blogspot.com to use with ubuntu

9. August 2009

it wasn’t easy to find software running under Ubunutu 9.04 that allows editing my blogger.com (blogspot.com) blog. My first choice, Drivel, wasn’t able to connect to blogger.com.

But there was a hint to check out the “Petrus Blogger“. And that was the solution! A nice Java-based application giving a bunch of possibilities to maintain your blog. Ok, it was a little tricky to make Petrus use a Proxy for initial configuration, but after getting it to work, it’s simly great! If you’re searching a small but powerful, Java-based Blogging client, Petrus for sure is worth a look.


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