The console printed:

Failed startup of context o.e.j.w.WebAppContext{/csns2,file:/home/mark/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/csns2/},/home/mark/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/csns2
java.lang.reflect.InvocationTargetException

Caused by: 
java.lang.ClassCastException: org.eclipse.wst.server.preview.internal.WTPErrorHandler cannot be cast to org.eclipse.jetty.servlet.ErrorPageErrorHandler

Nothing was printed to the log file. I have no idea what this error is. Any help appreciated.

EDIT: I was able to get past this particular error with the instructions found here http://stackoverflow.com/a/12292469/399741, up to Maven clean.