Just found this site 


http://www.rgagnon.com/javadetails/java-0014.html
lots of info on Runtime.exec() method.

it also has a lot of example on how to run 

launch CMD.EXE, grab stdin/stdout and push to stdin command to be interpreted by the shell. 

Launch a Windows CMD (or BAT) file and retrieve the errorlevel or exitcode

 

Launch a Unix script

 

etc