question: public GroupTree findGroup ( String fullyQualifiedGroupName ) { String [ ] groupKeys = fullyQualifiedGroupName . split ( "\\." ) ; GroupTree group = this ; for ( int i = 0 ; i < groupKeys . length && group != null ; i ++ ) { group = group . getSubGroup ( groupKeys [ i ] ) ; } return group ; }
target:  Finds the group for the given fully qualified name (dot separated) if existing, returning null otherwise.