A DESCRIPTION OF THE PROBLEM :
small mistake in the javax.swing.plaf.synth.Region API:
"RADIO_BUTTON_MENU_ITEM RegionButtonMenuItem region"

it should be:
"RADIO_BUTTON_MENU_ITEM RadioButtonMenuItem region"

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
"RADIO_BUTTON_MENU_ITEM RadioButtonMenuItem region"
ACTUAL -
"RADIO_BUTTON_MENU_ITEM RegionButtonMenuItem region"

URL OF FAULTY DOCUMENTATION :
http://java.sun.com/j2se/1.5.0/docs/api/