public static String regionNamesToString(final Collection<byte[]> regions) {
    final StringBuilder sb = new StringBuilder();
    final Iterator<byte[]> it = regions.iterator();
    sb.append("[");
    if (it.hasNext()) {
      sb.append(Bytes.toStringBinary(it.next()));
      while (it.hasNext()) {
        sb.append(", ");
        sb.append(Bytes.toStringBinary(it.next()));
      }
    }
    sb.append("]");
    return sb.toString();
  }
Returns Pertinent ServerStateNode or NULL if none found (Do not make modifications).
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java