From Jim Gish:

I just ran into an issue that took me more time to track down than I would have liked. I had set JT_HOME incorrectly and I got the error message "Cannot determine version of java to run jtreg"

This lead me to believe that I had not set the java to run properly, when in fact it was a second-level error caused by the fact that JT_HOME/lib/jtreg.jar didn't exist and it thus couldn't load com.sun.javatest.regtest.GetSystemProperty

If the following lines are inserted in the jtreg script, this would have saved me a lot of time:

if [ ! -r $JT_HOME/lib/jtreg.jar ];then
   echo "Invalid JT_HOME=$JT_HOME. Cannot find/read $JT_HOME/lib/jtreg.lib"
   exit 1;
fi