This article shows how to create stack traces from background java processes: Creating Java Stack Traces
Since a while (I think since I upgraded my Linux installation from Ubuntu 9.10 to 10.04), my Mozilla Firefox (3.6.3) did not recognize the Java plugin anymore. The interesting learning is that this does not really affect day-to-day internet usage – even though I am regularly browsing through the web, I noticed the missing applet functionality only very seldom, and it has never been a blocker for me in the last couple of months. I never really liked Java applets on web pages, and it seems that this technique has now almost been superseeded by other technologies like flash. Nevertheless, yesterday I was forced to make the Java browser plugin work on my installation because the german postal service DHL requires it for printing out stamps. Earlier they used a scripted PDF document which could be printed with Acrobat reader and which connected to the DHL web site to ensure it is printed only once, but due to customer complaints they switched to a Java applet based solution (at least, the PDF approach also worked in Linux 😉 ) So, I did two things to make the Java plugin work again:
- Ubuntu has removed the SUN (now aka Oracle) java packages from their repository. Since I suspected an installation issue, I installed the current JDK from the Oracle web site (Ubuntu now only contains OpenJDK, but I do not yet have experience with it)
- Installing the JDK was not sufficient. Additionally, I had to link /etc/alternatives/firefox-javaplugin.so to the library libnpjp2.so below the jre/lib/i386/ directory, instead of the library libjavaplugin_oji.so below the jre/plugin/i386/ns7 directory.