I have been using cqlsh (and --cql3) successfully for a few weeks.
But yesterday it stopped working, with the all too familiar,

     "Connection error: Could not connect to localhost:9160"

Still got the same message, 9160, after I changed the rpc_port in the yaml file to 9161 or 9159.

I recently installed the Maven plugin in Eclipse, so I thought that might be the problem. (My prototyping/research code is so simple that I've used Eclipse's builds with no problems for years.  Maven would be overkill.)

I reread the various Cassandra docs, reinstalled Cassandra (apache-cassandra-1.1.7) recreated the var/lib directories, rebooted my machine, restarted Eclipse, that's about all I could think of.  Eclipse was going to be the next stage for me after various cqlsh experiments, so it shouldn't have any effect on the CLI.    I'm no expert on ports and the like. I don't do web servers/clients.  My expertise is in the Java/Swing systems I build for NLP research.  Now that I'm retired and working from home, I can't just walk down the hall and talk with our systems experts.

  - Bob Futrelle