LinkedHashMap table;
for each element e of array A
    if table.get(e) != null
        table.put( e, table.get(e) + 1 )
    else
       table.put( e, 0 )

//Do the same for array B
for each element e of array B
    if table.get(e) != null
        table.put( e, table.get(e) + 1 )
    else
       table.put( e, 0 )

Collection union(Collection coll1, Collection coll2) {
    Set union = new HashSet(coll1);
    union.addAll(new HashSet(coll2));
    return union;
}

Collection intersect(Collection coll1, Collection coll2) {
    Set intersection = new HashSet(coll1);
    intersection.retainAll(new HashSet(coll2));
    return intersection;
}

Collection nonOverLap(Collection coll1, Collection coll2) {
   Collection result = union(coll1, coll2);
   result.removeAll(intersect(coll1, coll2));
   return result;
}