Using Java Listeners in RPE

I am using RPE 2.1.1 to create a document.  However, we (our company) would like to use a dialog box that uses listeners to auto-fill a combo box after the selection from another combo box in the dialog.  However, when I try to use the normal Java listener (private void myListener()), RPE gives me an error saying that private is a reserved word.  If I remove the word private, though, I get an error saying that I'm missing a semicolon before the statement.

Has anyone used listeners in RPE and if so, how do I set them up for a specific object on the dialog box?

Chris