The man page for javac has a line in it which is as follows:

"javac_g is a non-optimized version of javac suitable for use with
debuggers like jdb(1)."

javac -g MyClass will list the local variables.
javac_g MyClass will not.

This javac_g line is *very* confusing. It means - for use if you want
to debug javac. I don't think this should be on the man page.