Issue: The Exec Helper is installed, but Contrast isn't starting
You must reload the shell for the installer to take effect.
When you restart your web application server with a Daemon Manager like systemd or an init.v script, this is done for you; but, if you're trying to start up a web application in your user's shell (e.g., java -jar webgoat.jar), you must first reload your shell.
Issue: I don't know where the Exec Helper logs messages
The Exec Helper logs messages to the host's Syslog service using the identifier "Contrast". The Exec Helper uses the "user.warn" and "user.debug" Syslog facility and level, respectively.
Newer systems which use systemd, including EL7 and Ubuntu 16.04, store Syslog messages in the systemd journal. Use journalctl to view the messages (i.e., journalctl -t Contrast). Traditional init.v systems, including EL6 and Ubuntu 14.04, store Syslog messages in the file /var/log/messages by default.
If there aren't any logs in either of these storage locations, verify Syslog configuration /etc/syslog.conf; the host may be configured to drop the message types or log level used by the Exec Helper.