Check the version of java you are running.
java -version
Unfortunately, edu.stanford.nlp.util.CoreMap does not compile under
many versions of OpenJDK. However, the most recent versions of
OpenJDK do successfully compile the source. If this is the issue,
either upgrade or switch to Sun JDK.
You can discuss other topics with Stanford NLP developers and users by
joining
the java-nlp-user mailing list
(via a webpage). Or you can send other questions and feedback to
java-nlp-support@lists.stanford.edu.