I know java webstart is running under a secure sandbox. Is it possible to include a .dll/.exe in the jar (or have the webstart download it to the local machine) and then execute it (using Runtime.exec or process,etc)
Please Advise. Any suggestion/comment is welcome!
Yes. You have to wrap the .dll in a .jar file, and reference it in your .jnlp file using <nativelib>
See here for a more detailed description.
If you want to run an executable, then your best bet is to package it up in your .jar as a resource, explode it to (say) a temporary directory, and then run it using the normal Process/Runtime mechanism.