private List<IAtom> getUnion(List<IAtom> list1, List<IAtom> list2) {
        // FIXME: the JavaDoc does not describe what happens: that vec1 gets to be the union!
        // jm: pretty sure retainAll would do the trick here but don't want to change the
        //     functionality as item only present in list1 are not removed (i.e. not union)
        List<IAtom> is = new ArrayList<IAtom>(list1);
        for (int f = list2.size() - 1; f > -1; f--) {
            if (!list1.contains(list2.get(f))) is.add(list2.get(f));
        }
        return is;
    }
private List < IAtom > getUnion ( List < IAtom > list1 , List < IAtom > list2 ) { List < IAtom > is = new ArrayList < IAtom > ( list1 ) ; for ( int f = list2 . size ( ) - 1 ; f > - 1 ; f -- ) { if ( ! list1 . contains ( list2 . get ( f ) ) ) is . add ( list2 . get ( f ) ) ; } return is ; }
Returns a Vector that contains the union of Vectors vec1 and vec2

@param   list1  The first vector
@param   list2  The second vector
@return the union of the two list