Ran into the same exact issue with RHEL 6 Desktop, as soon as I removed CW Control it stopped spitting out those errors every 5 seconds.
Limited to OS X SSH and Linux gnome-terminal SSH, this doesn't happen in Putty. Java version is jre1.8.0_131 which is pretty recent.
There was no trace of these errors in the ~/.xsession-errors file or any file in /var/log so I expect the CW control agent is not playing well with any current X11 displays. Even when X11 forwarding was not enabled via ssh the errors would still occur. I think this is in part due to the default java startup option: java -XX:+DisplayVMOutputToStderr
This JVM output shouldn't be sent to Stderr as all users see them via terminal and need to go directly to file or the management console.
Please improve upon the linux agent as we now have to find a new monitoring solution for that client.
Customer support service by UserEcho