*
   * <p>Why <i>not</i> just add {@code SuppressWarnings}? The problem is that this method is
   * typically useful for {@code return} statements. That leaves the code with two options: Either
   * add the suppression to the whole method (which turns off checking for a large section of code),
   * or extract a variable, and put the suppression on that. However, a local variable typically

   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this class leaves the specific choice of
   * hash code unspecified, unlike the Java 8+ equivalent.
   */
  @Override
  public abstract int hashCode();

  /**
   * Returns a string representation for this instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this class leaves the specific string

 * including those in many JDK classes.
 *
 * <p>{@code Object.hashCode} implementations tend to be very fast, but have weak collision
 * prevention and <i>no</i> expectation of bit dispersion. This leaves them perfectly suitable for
 * use in hash tables, because extra collisions cause only a slight performance hit, while poor bit

          BinaryOperator<V> mergeFunction) {
    return CollectCollectors.toImmutableMap(keyFunction, valueFunction, mergeFunction);
  }

  /**
   * Returns the empty map. This map behaves and performs comparably to {@link
   * Collections#emptyMap}, and is preferable mainly for consistency and maintainability of your
   * code.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.

    try {
      builder.orderEntriesByValue(Ordering.natural());
      fail("Expected IllegalStateException");
    } catch (IllegalStateException expected) {
    }
  }

  @GwtIncompatible // we haven't implemented this
  public void testBuilder_orderEntriesByValue_keepingLast() {
    ImmutableMap.Builder<String, Integer> builder =
        new Builder<String, Integer>()
            .orderEntriesByValue(Ordering.natural())

    assertThat(transformation.inverse().inverse()).isSameInstanceAs(transformation);
  }

  /**
   * Asserts that {@code transformation} behaves as expected for {@link
   * LinearTransformation#forNaN}.
   */
  static void assertLinearTransformationNaN(LinearTransformation transformation) {
    assertThat(transformation.isHorizontal()).isFalse();

   * B>`, convertAll could accept and return iterables with nullable element types. In both cases,
   * we've chosen to instead use a signature that benefits existing users -- and is still safe.
   *
   * For convertAll, I haven't looked as closely at *how* much existing users benefit, so we should
   * keep an eye out for problems that new users encounter. Note also that convertAll could support

 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck/JSR166TestCase.java?revision=1.90
 * (We have made some trivial local modifications (commented out
 * uncompilable code).)
 */

package com.google.common.util.concurrent;

    assertEquals(localCacheOne.removalListener, localCacheTwo.removalListener);
    assertEquals(localCacheOne.ticker, localCacheTwo.ticker);

    // serialize the reconstituted version to be sure we haven't lost the ability to reserialize
    LocalLoadingCache<Object, Object> three = SerializableTester.reserialize(two);
    LocalCache<Object, Object> localCacheThree = three.localCache;

    assertEquals(localCacheOne.removalListener, localCacheTwo.removalListener);
    assertEquals(localCacheOne.ticker, localCacheTwo.ticker);

    // serialize the reconstituted version to be sure we haven't lost the ability to reserialize
    LocalLoadingCache<Object, Object> three = SerializableTester.reserialize(two);
    LocalCache<Object, Object> localCacheThree = three.localCache;