If you’re trying to build netbeans from the git repository, and you’re on Ubuntu 7.10, you’ll probably get:
james@madra:~/dev/netbeans$ ant
Buildfile: build.xml
BUILD FAILED
/home/james/dev/netbeans/build.xml:45: The following error occurred while executing this line:
/home/james/dev/netbeans/nbbuild/build.xml:72: No supported regular expression matcher found: java.lang.ClassNotFoundException: org.apache.tools.ant.util.regexp.Jdk14RegexpMatcher
Total time: 0 seconds
To fix, just install ant-optional:
sudo apt-get install ant-optional
You’ll find building instructions here.