static void addAll(Collection c, Iterable b) { if (c != null && b != null) for (A a : b) c.add(a); } static void addAll(Collection c, Collection b) { if (c != null && b != null) c.addAll(b); } static void addAll(Collection c, A... b) { if (c != null) c.addAll(Arrays.asList(b)); }