// we try hard to make them robust in practice.  We could additionally try to add in a system
    // load timeout multiplier.  Or we could try to use a CPU time bound instead of wall clock time
    // bound.  But these ideas are harder to implement.  We do not try to detect or handle a
    // user-specified -XX:+DisableExplicitGC.
    //
    // TODO(user): Consider using
    // java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage()

    // we try hard to make them robust in practice.  We could additionally try to add in a system
    // load timeout multiplier.  Or we could try to use a CPU time bound instead of wall clock time
    // bound.  But these ideas are harder to implement.  We do not try to detect or handle a
    // user-specified -XX:+DisableExplicitGC.
    //
    // TODO(user): Consider using
    // java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage()

    ListenableFuture -- but is also available in a second "version" that
    contains com.google.common.util.concurrent.ListenableFuture class, without
    any other Guava classes. The idea is:

    - If users want only ListenableFuture, they depend on listenablefuture-1.0.

    - If users want all of Guava, they depend on guava, which, as of Guava
    27.0, depends on

      return;
    }

    Set<Entry<K, V>> entrySet = map.entrySet();
    if (supportsRemove) {
      try {
        entrySet.retainAll(null);
        // Returning successfully is not ideal, but tolerated.
      } catch (NullPointerException tolerated) {
      }
    } else {
      try {
        entrySet.retainAll(null);
        // We have to tolerate a successful return (Sun bug 4802647)

  }

  @GwtIncompatible // String.toUpperCase() has browser semantics
  public void testEqualsIgnoreCaseUnicodeEquivalence() {
    // Note that it's possible in future that the JDK's idea to toUpperCase() or equalsIgnoreCase()
    // may change and break assumptions in this test [*]. This is not a bug in the implementation of
    // Ascii.equalsIgnoreCase(), but it is a signal that its documentation may need updating as

  @CollectionSize.Require(ZERO)
  public void testRetainAll_nullCollectionReferenceEmptySubject() {
    try {
      collection.retainAll(null);
      // Returning successfully is not ideal, but tolerated.
    } catch (NullPointerException tolerated) {
    }
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)

        };
    try {
      Hashing.hmacMd5(badKey);
      fail();
    } catch (IllegalArgumentException expected) {
    } catch (NullPointerException toleratedOnAndroid) {
      // TODO(cpovirk): In an ideal world, we'd check here that we're running on Android.
    }
  }

  public void testEmptyInputs() throws Exception {
    String knownOutput = "8cbf764cbe2e4623d99a41354adfd390";

opportunity for showing off her knowledge, as there was no one to
listen to her, still it was good practice to say it over) `--yes,
that's about the right distance--but then I wonder what Latitude
or Longitude I've got to?'  (Alice had no idea what Latitude was,
or Longitude either, but thought they were nice grand words to
say.)

  Presently she began again.  `I wonder if I shall fall right
THROUGH the earth!  How funny it'll seem to come out among the

 *       check for thread assertion failures.
 *   <li>All delays and timeouts must use one of the constants {@code SHORT_DELAY_MS}, {@code
 *       SMALL_DELAY_MS}, {@code MEDIUM_DELAY_MS}, {@code LONG_DELAY_MS}. The idea here is that a
 *       SHORT is always discriminable from zero time, and always allows enough time for the small
 *       amounts of computation (creating a thread, calling a few methods, etc) needed to reach a

  //    Imagine:
  //    guard.lock();
  //    try { /* monitor locked and guard satisfied here */ }
  //    finally { guard.unlock(); }
  // Here are Justin's design notes about this:
  //
  // This idea has come up from time to time, and I think one of my
  // earlier versions of Monitor even did something like this. I ended
  // up strongly favoring the current interface.
  //