Choose directory into which the executable and built image should be stored. This is the OVM-EXE-DIR. Again OVM-EXE-DIR could be OVM-DIR.
$ cd OVM-EXE-DIR
$ OVM-BIN-DIR/bin/gen-ovm -main=HelloWorld \
-classpath=CLASSPATH TO HelloWorld.class
If you installed ovm then you could use OVM-INSTALL-DIR/bin/gen-ovm
Have a cup of coffee while the image is built.