code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.Collections;
  
  /*
   * Copyright 2005 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 6301089
   * @summary test Collections.newSetFromMap
   * @author Martin Buchholz
   */
  
  import java.util.*;
  
  public class SetFromMap {
      static volatile int passed = 0, failed = 0;
      static void pass() { passed++; }
      static void fail() { failed++; Thread.dumpStack(); }
      static void unexpected(Throwable t) { failed++; t.printStackTrace(); }
      static void check(boolean cond) { if (cond) pass(); else fail(); }
      static void equal(Object x, Object y) {
          if (x == null ? y == null : x.equals(y)) pass();
          else {System.out.println(x + " not equal to " + y); fail(); }}
  
      public static void main(String[] args) throws Throwable {
          try { realMain(); } catch (Throwable t) { unexpected(t); }
  
          System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
          if (failed > 0) throw new Exception("Some tests failed");
      }
  
      private static void realMain() throws Throwable {
          try {
              Map<String,Boolean> m = new IdentityHashMap<String,Boolean>();
              Set<String> s = Collections.newSetFromMap(m);
              String foo1 = new String("foo");
              String foo2 = new String("foo");
              String bar = new String("bar");
              check(s.add(foo1));
              check(s.add(foo2));
              check(s.add(bar));
              equal(s.size(), 3);
              check(s.contains(foo1));
              check(s.contains(foo2));
              check(! s.contains(new String(foo1)));
          } catch (Throwable t) { unexpected(t); }
      }
  }
  