* Benchmarks (as of December 2011) show that:
 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.
 *   <li>for nested locking, the cost increases with the depth of the nesting:
 *       <ul>
 *         <li>2 levels: average of 64ns per lock()/unlock()
 *         <li>3 levels: average of 77ns per lock()/unlock()

 *
 * <p>Unpacking this definition:
 *
 * <ul>
 *   <li><b>block of data:</b> the input for a hash function is always, in concept, an ordered byte
 *       array. This hashing API accepts an arbitrary sequence of byte and multibyte values (via
 *       {@link Hasher}), but this is merely a convenience; these are always translated into raw
 *       byte sequences under the covers.

   *
   * <ul>
   *   <li>it may split surrogate pairs
   *   <li>it may split characters and combining characters
   *   <li>it does not consider word boundaries
   *   <li>if truncating for display to users, there are other considerations that must be taken
   *       into account
   *   <li>the appropriate truncation indicator may be locale-dependent

 * multiset. Undefined behavior and bugs will result.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableMultiset}
 *   <li>{@link ImmutableSortedMultiset}
 *   <li>{@link HashMultiset}
 *   <li>{@link LinkedHashMultiset}
 *   <li>{@link TreeMultiset}
 *   <li>{@link EnumMultiset}
 *   <li>{@link ConcurrentHashMultiset}
 * </ul>
 *

 * actions taken by the java garbage collection system:
 *
 * <ul>
 *   <li>invoking the {@code finalize} methods of unreachable objects
 *   <li>clearing weak references to unreachable referents
 *   <li>enqueuing weak references to unreachable referents in their reference queue
 * </ul>
 *

 *   <li>Convert multiple instances "forward" using {@code converter.convertAll(as)}.
 *   <li>Convert in the "backward" direction using {@code converter.reverse().convert(b)} or {@code
 *       converter.reverse().convertAll(bs)}.
 *   <li>Use {@code converter} or {@code converter.reverse()} anywhere a {@link
 *       java.util.function.Function} is accepted (for example {@link java.util.stream.Stream#map
 *       Stream.map}).

   * consistentHash(h, n)} equals:
   *
   * <ul>
   *   <li>{@code n - 1}, with approximate probability {@code 1/n}
   *   <li>{@code consistentHash(h, n - 1)}, otherwise (probability {@code 1 - 1/n})
   * </ul>
   *
   * <p>This method is suitable for the common use case of dividing work among buckets that meet the
   * following conditions:
   *
   * <ul>
   *   <li>You want to assign the same fraction of inputs to each bucket.

 *
 * <p>{@code CharSource} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a reader:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned reader is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

     * <ul>
     * <li><code>type</code>がパラメータ化された型の配列でない場合は<code>null</code>を返します。</li>
     * <li><code>type</code>が<code>Class</code>の場合はそのまま返します。</li>
     * <li><code>type</code>がパラメータ化された型の場合はその原型を返します。</li>
     * <li><code>type</code>がワイルドカード型の場合は(最初の)上限境界を返します。</li>
     * <li><code>type</code>が型変数の場合はその変数の実際の型引数を返します。</li>
     * <li><code>type</code>が配列の場合はその要素の実際の型の配列を返します。</li>

 * webservers, RPC servers and timers.
 *
 * <p>The normal lifecycle of a service is:
 *
 * <ul>
 *   <li>{@linkplain State#NEW NEW} -&gt;
 *   <li>{@linkplain State#STARTING STARTING} -&gt;
 *   <li>{@linkplain State#RUNNING RUNNING} -&gt;
 *   <li>{@linkplain State#STOPPING STOPPING} -&gt;
 *   <li>{@linkplain State#TERMINATED TERMINATED}
 * </ul>
 *