@Override
  public synchronized void clear() {
    list = Collections.emptyList();
  }
Returns a reference to the unmodifiable list currently backing the SortedList. Changes to the
SortedList will not be reflected in this list. Use this method to get a reference for iterating
over using the RandomAccess pattern.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/SortedList.java