* @throws IllegalArgumentException if any two keys are equal according to their natural ordering
   */
  public static <K, V> ImmutableSortedMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    // Hack around K not being a subtype of Comparable.
    // Unsafe, see ImmutableSortedSetFauxverideShim.
    @SuppressWarnings("unchecked")
    Ordering<K> naturalOrder = (Ordering<K>) NATURAL_ORDER;
    return copyOfInternal(map, naturalOrder);

    assertEquals(refreshKey + suffix, map.get(refreshKey));
  }

  public void testInvalidateDuringLoading() throws InterruptedException, ExecutionException {
    // computation starts; invalidate() is called on the key being computed, computation finishes
    final CountDownLatch computationStarted = new CountDownLatch(2);
    final CountDownLatch letGetFinishSignal = new CountDownLatch(1);

   * @throws IllegalArgumentException if any two keys are equal according to their natural ordering
   */
  public static <K, V> ImmutableSortedMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    // Hack around K not being a subtype of Comparable.
    // Unsafe, see ImmutableSortedSetFauxverideShim.
    @SuppressWarnings("unchecked")
    Ordering<K> naturalOrder = (Ordering<K>) NATURAL_ORDER;
    return copyOfInternal(map, naturalOrder);

  //   is). If we wanted to be strict about it, we could store the unpark() time in the Waiter node
  //   and we could use that to make a decision about whether or not we timed out prior to being
  //   unparked.

  /**
   * {@inheritDoc}
   *
   * <p>The default {@link AbstractFuture} implementation throws {@code InterruptedException} if the

    assertEquals(refreshKey + suffix, map.get(refreshKey));
  }

  public void testInvalidateDuringLoading() throws InterruptedException, ExecutionException {
    // computation starts; invalidate() is called on the key being computed, computation finishes
    final CountDownLatch computationStarted = new CountDownLatch(2);
    final CountDownLatch letGetFinishSignal = new CountDownLatch(1);

    }
  }

  /** A weakly referenced value that also has a reference to its containing entry. */
  interface WeakValueReference<K, V, E extends InternalEntry<K, V, E>> {
    /**
     * Returns the current value being referenced, or {@code null} if there is none (e.g. because
     * either it got collected, or {@link #clear} was called, or it wasn't set in the first place).
     */
    @CheckForNull
    V get();

   * Iterables#filter(Iterable, Class)} for related functionality.)
   *
   * <p><b>Java 8+ users:</b> many use cases for this method are better addressed by {@link
   * java.util.stream.Stream#filter}. This method is not being deprecated, but we gently encourage
   * you to migrate to streams.
   */
  // TODO(kevinb): how to omit that last sentence when building GWT javadoc?
  public static <E extends @Nullable Object> Set<E> filter(

   *
   * <p>It appears that properly handling recursive type bounds in the presence of implicit type
   * bounds is not easy. For now we punt, hoping that this defect should rarely cause issues in real
   * code.
   *
   * @param formalType is {@code Foo<formalType>} a supertype of {@code Foo<T>}?

   * For example, the cache may evict an entry because it hasn't been used recently or very often.
   *
   * <p>If {@code maximumSize} is zero, elements will be evicted immediately after being loaded into
   * cache. This can be useful in testing, or to disable caching temporarily.
   *
   * <p>This feature cannot be used in conjunction with {@link #maximumWeight}.
   *

  //
  // See: http://cs.oswego.edu/pipermail/concurrency-interest/2015-January/013800.html
  // For a (long) discussion about this specific issue and the general futility of life.
  //
  // For the time being we are OK with the problem discussed above since it requires a caller to
  // introduce a very specific kind of data-race. And given the other operations performed by these