code: public final void removeElementsAt(int firstindex, int count)
    {
      if (tc.isEntryEnabled())
        SibTr.entry(
          tc,
          "removeElementsAt",
          new Object[] { new Integer(firstindex), new Integer(count)});
  
      removeRange(firstindex, firstindex + count);
  
      if (tc.isEntryEnabled())
        SibTr.exit(tc, "removeElementsAt");
    }
docs: Deletes the components in [firstindex, firstindex+ count-1]. Each component in
  this vector with an index greater than firstindex+count-1
  is shifted downward.
  The firstindex+count-1 must be a value less than the current size of the vector.
  
  @exception  ArrayIndexOutOfBoundsException  if the indices was invalid.