Removing and re-installing worked for me.
Particulars:
- It had been about a year since I had run maven on this Linux machine.
- Java had been upgraded from 7 to 8 (but other changes have also occurred).
- My M2_HOME/M3_HOME was not defined (so clearing this wasn't a solution).
- Running the
mvn script in debug (bash -x mvn) showed that the missing jar file was explicitly requested.
- I could only find an older version of the
org.codehaus.plexus.classworlds package/module.
Since it wasn't clear how to independently update the org.codehaus jars, I let apt-get pull in what it needed. Problem solved.
