### Question:
RetriveUnrepeats { public static String contactUids(String oldUids, String[] newUids) { StringBuffer result = new StringBuffer(); HashSet<String> hs = new HashSet<>(); for (String uid : oldUids.split(",")) { hs.add(uid); } for (String uid : newUids) { hs.add(uid); } Iterator<String> iterator = hs.iterator(); while (iterator.hasNext()) { result.append(iterator.next()).append(","); } if (result.length() > 1) { return result.toString().substring(0, result.length() - 1); } else { return ""; } }  static String unRepeatUids(String oldUids, String[] newUids); static String contactUids(String oldUids, String[] newUids);  }### Answer:
@Test public void testStressContactUids() throws Exception { assertEquals(5676, RetriveUnrepeats.contactUids(oldFans, newFans.split(",")).split(",").length); }