A couple of Linux problems and their solutions

This page contains a couple of problems I've stumbled upon during my time on Linux. The purpose of this page is solely to present a specific solution to my specific problems - mostly because I wasn't able to simply solve them by googling. Maybe they're useful to someone.

ant aborts with Unable to load default ProjectHelper due to java.lang.NoClassDefFoundError: org/xml/sax/SAXException

I tried to use the build tool ant for building a Java application with the J2SDK 1.3.1 on my Debian/unstable box. So I called apt-get install ant and ran ant -f build-2.xml only to be bitten by this evil error message:

Unable to load default ProjectHelper due to java.lang.NoClassDefFoundError: org/xml/sax/SAXException

The problem was that my CLASSPATH was empty. All I had to do was point it to the two jars from the libxerces2-java package:

export CLASSPATH=/usr/share/java/xercesImpl.jar:/usr/share/java/xmlParserAPIs.jar:$CLASSPATH