* load on the garbage collector by only using a constant number of internal objects.
 *
 * <p>This class should not be assumed to be universally superior to {@code
 * java.util.LinkedHashMap}. Generally speaking, this class reduces object allocation and memory
 * consumption at the price of moderately increased constant factors of CPU. Only use this class
 * when there is a specific reason to prioritize memory over CPU.
 *

    }
  }

  /** Returns the {@code Class} object of arrays with {@code componentType}. */
  static Class<?> getArrayClass(Class<?> componentType) {
    // TODO(user): This is not the most efficient way to handle generic
    // arrays, but is there another way to extract the array class in a
    // non-hacky way (i.e. using String value class names- "[L...")?
    return Array.newInstance(componentType, 0).getClass();
  }

 * similar to those in this class for non-precondition checks.
 *
 * <h3>{@code java.util.Objects.requireNonNull()}</h3>
 *
 * <p>Projects which use {@code com.google.common} should generally avoid the use of {@link
 * java.util.Objects#requireNonNull(Object)}. Instead, use whichever of {@link
 * #checkNotNull(Object)} or {@link Verify#verifyNotNull(Object)} is appropriate to the situation.

   * is. The {@code equals} and {@code hashCode} methods of the returned multimap are meaningless,
   * since there is not a definition of {@code equals} or {@code hashCode} for general collections,
   * and {@code get()} will return a general {@code Collection} as opposed to a {@code List} or a
   * {@code Set}.
   *
   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned

        ImmutableList.<E>asImmutableList(contents, uniques), comparator);
  }

  /**
   * Returns a builder that creates immutable sorted sets with an explicit comparator. If the
   * comparator has a more general type than the set being generated, such as creating a {@code
   * SortedSet<Integer>} with a {@code Comparator<Number>}, use the {@link Builder} constructor
   * instead.
   *

 * <p>For field types and method return types, you should generally use the immutable type (such as
 * {@link ImmutableList}) instead of the general collection interface type (such as {@link List}).
 * This communicates to your callers all of the semantic guarantees listed above, which is almost
 * always very useful information.
 *
 * <p>On the other hand, a <i>parameter</i> type of {@link ImmutableList} is generally a nuisance to

  //    the initial write (just stronger guarantees if it does).
  //
  // 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

   *
   * @throws IllegalStateException if the instance is absent ({@link #isPresent} returns {@code
   *     false}); depending on this <i>specific</i> exception type (over the more general {@link
   *     RuntimeException}) is discouraged
   */
  public abstract T get();

  /**
   * Returns the contained instance if it is present; {@code defaultValue} otherwise. If no default

 * <p>For field types and method return types, you should generally use the immutable type (such as
 * {@link ImmutableList}) instead of the general collection interface type (such as {@link List}).
 * This communicates to your callers all of the semantic guarantees listed above, which is almost
 * always very useful information.
 *
 * <p>On the other hand, a <i>parameter</i> type of {@link ImmutableList} is generally a nuisance to

  static final boolean GENERATE_CANCELLATION_CAUSES;

  static {
    // System.getProperty may throw if the security policy does not permit access.
    boolean generateCancellationCauses;
    try {
      generateCancellationCauses =
          Boolean.parseBoolean(
              System.getProperty("guava.concurrent.generate_cancellation_cause", "false"));
    } catch (SecurityException e) {