This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
Java is Write-Once/Run-Anywhere, so direct invocation of any OS-specific service or non-Java code isn't possible. If your iSeries system allows you to present these commands as web services or remote method calls, you might be able to get away with pure Java. Otherwise, your best bet is to just supply JNI glue API modules. Or, if possible run them as command-line processes, via the java Runtime exec functionality.
Customer surveys are for companies who didn't pay proper attention to begin with.