code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.TreeMap;
  
  /*
   * Copyright 1999 Sun Microsystems, Inc.  All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
   * CA 95054 USA or visit www.sun.com if you need additional information or
   * have any questions.
   */
  
  /*
   * @test
   * @bug 4252490
   * @summary The firstKey and lastKey
   */
  
  import java.util.*;
  
  public class SubMap {
      public static void main(String args[]) throws Exception {
          SortedMap m = new TreeMap();
          m.put(new Integer(1), new Integer(1));
          m.put(new Integer(2), new Integer(2));
          m.put(new Integer(3), new Integer(3));
          SortedMap m2 = m.subMap(new Integer(2), new Integer(2));
  
          boolean exc = false;
          try {
              m2.firstKey();
          } catch(NoSuchElementException e) {
              exc = true;
          }
          if (!exc)
              throw new Exception("first key");
  
          exc = false;
          try {
              m2.lastKey();
          } catch(NoSuchElementException e) {
              exc = true;
          }
          if (!exc)
              throw new Exception("last key");
  
          SortedMap m3 = m.subMap(new Integer(2), new Integer(3));
          if (!m3.firstKey().equals(new Integer(2)))
              throw new Exception("first key wrong");
          if (!m3.lastKey().equals(new Integer(2)))
              throw new Exception("last key wrong");
  
          SortedSet s = new TreeSet();
          s.add(new Integer(1));
          s.add(new Integer(2));
          s.add(new Integer(3));
          SortedSet s2 = s.subSet(new Integer(2), new Integer(2));
  
          exc = false;
          try {
              s2.first();
          } catch(NoSuchElementException e) {
              exc = true;
          }
          if (!exc)
              throw new Exception("first element");
  
          exc = false;
          try {
              s2.last();
          } catch(NoSuchElementException e) {
              exc = true;
          }
          if (!exc)
              throw new Exception("last element");
  
          SortedSet s3 = s.subSet(new Integer(2), new Integer(3));
          if (!s3.first().equals(new Integer(2)))
              throw new Exception("first element wrong");
          if (!s3.last().equals(new Integer(2)))
              throw new Exception("last element wrong");
      }
  }
  