*
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}
 * reference. It allows you to represent "a {@code T} that must be present" and a "a {@code T} that
 * might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no

    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderKeysBy(
        new Ordering<String>() {
          @Override
          public int compare(String left, String right) {
            return left.length() - right.length();
          }
        });
    builder.put("cc", 4);
    builder.put("a", 2);
    builder.put("bb", 6);
    ImmutableSetMultimap<String, Integer> multimap = builder.build();

                (byte) 0x05, (byte) 0x06, (byte) 0x07, (byte) 0x08
              },
              0x89abcdef,
              0x0123456789abcdefL, // asInt/asLong as above, due to equal eight first bytes
              "efcdab89674523010102030405060708"),
          new ExpectedHashCode(
              new byte[] {(byte) 0xdf, (byte) 0x9b, (byte) 0x57, (byte) 0x13},
              0x13579bdf,
              null,

  int hashCode();

  /**
   * Returns a readable string representation of this range set. For example, if this {@code
   * RangeSet} consisted of {@code Range.closed(1, 3)} and {@code Range.greaterThan(4)}, this might
   * return {@code " [1..3](4..+∞)}"}.
   */
  @Override
  String toString();

      inverse.delegate.remove(entry.getValue());
      /*
       * Remove the mapping in inverse before removing from esDelegate because
       * if entry is part of esDelegate, entry might be invalidated after the
       * mapping is removed from esDelegate.
       */
      esDelegate.remove(entry);
      return true;
    }

    @Override
    public Iterator<Entry<K, V>> iterator() {

    return new SingletonImmutableSet<>(element);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**

      UnconditionalValueHolder valueHolder = addUnconditionalHolder();
      valueHolder.value = value;
      valueHolder.name = checkNotNull(name);
      return this;
    }

    // Holder object for values that might be null and/or empty.
    static class ValueHolder {
      @CheckForNull String name;
      @CheckForNull Object value;
      @CheckForNull ValueHolder next;
    }

    /**

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;

/**
 * Tests relating to cache expiration: make sure entries expire at the right times, make sure
 * expired entries don't show up, etc.
 *
 * @author mike nonemacher
 */
@SuppressWarnings("deprecation") // tests of deprecated method
public class CacheExpirationTest extends TestCase {

         *
         * Sun bug 6665356 is an additional complication. Until OpenJDK 7, javac
         * doesn't recognize this kind of cast as unchecked cast. Neither does
         * Eclipse 3.4. Right now, this suppression is mostly unnecessary.
         */
        @SuppressWarnings("unchecked")
        MultiExceptionListIterator multiExceptionListIterator =
            (MultiExceptionListIterator) reference;

    /*
     * These gymnastics are a little confusing. Basically this class has neither legacy nor
     * non-legacy behavior; it just needs to let the behaviors of the backing converters shine
     * through (which might even differ from each other!). So, we override the correctedDo* methods,
     * after which the do* methods should never be reached.
     */

    @Override
    protected C doForward(A a) {