Start SwingSet2. Press F10 to move focus to the menu bar. The file menu will be open. Can use up/down and VO will speak the items. Press right arrow to move to next menu. VO will not speak items when up/down is used (but it will speak them if control option up/down is used.

The workaround is to use the Mac menu system by starting the app with:
-Dapple.laf.useScreenMenuBar=true