@VisibleForTesting
  static WildcardType supertypeOf(Type lowerBound) {
    return new WildcardTypeImpl(new Type[] {lowerBound}, new Type[] {Object.class});
  }

  /**
   * Returns a human-readable string representation of {@code type}.
   *
   * <p>The format is subject to change.
   */
  static String toString(Type type) {
    return (type instanceof Class) ? ((Class<?>) type).getName() : type.toString();

  StringReader generateStringReader() {
    return new StringReader(generateString());
  }

  @Generates
  Reader generateReader() {
    return generateStringReader();
  }

  @Generates
  Readable generateReadable() {
    return generateReader();
  }

  @Generates
  Buffer generateBuffer() {
    return generateCharBuffer();
  }

  @Generates
  CharBuffer generateCharBuffer() {

 * <td>{@link #base16()}
 * <td>0-9 A-F
 * <td>2.00
 * <td>N/A
 * <td>Traditional hexadecimal. Defaults to upper case.
 * <tr>
 * <td>{@link #base32()}
 * <td>A-Z 2-7
 * <td>1.60
 * <td>=
 * <td>Human-readable; no possibility of mixing up 0/O or 1/I. Defaults to upper case.
 * <tr>
 * <td>{@link #base32Hex()}
 * <td>0-9 A-V
 * <td>1.60
 * <td>=

    } else {
      addPendingString(builder); // delegates to addDoneString if future completes midway
    }
    return builder.append("]").toString();
  }

  /**
   * Provide a human-readable explanation of why this future has not yet completed.
   *
   * @return null if an explanation cannot be provided (e.g. because the future is done).
   * @since 23.0
   */
  @CheckForNull

  StringReader generateStringReader() {
    return new StringReader(generateString());
  }

  @Generates
  Reader generateReader() {
    return generateStringReader();
  }

  @Generates
  Readable generateReadable() {
    return generateReader();
  }

  @Generates
  Buffer generateBuffer() {
    return generateCharBuffer();
  }

  @Generates
  CharBuffer generateCharBuffer() {

    extends AbstractMap<K, V> implements ConcurrentMap<K, V>, Serializable {

  /*
   * The basic strategy is to subdivide the table among Segments, each of which itself is a
   * concurrently readable hash table. The map supports non-blocking reads and concurrent writes
   * across different segments.
   *
   * The page replacement algorithm's data structures are kept casually consistent with the map. The

 * supported by future versions of this library. However, serial forms generated by newer versions
 * of the code may not be readable by older versions of the code (e.g., a serialized Bloom filter
 * generated today may <i>not</i> be readable by a binary that was compiled 6 months ago).
 *
 * <p>As of Guava 23.0, this class is thread-safe and lock-free. It internally uses atomics and

          // io types
          .put(InputStream.class, new ByteArrayInputStream(new byte[0]))
          .put(ByteArrayInputStream.class, new ByteArrayInputStream(new byte[0]))
          .put(Readable.class, new StringReader(""))
          .put(Reader.class, new StringReader(""))
          .put(StringReader.class, new StringReader(""))
          .put(Buffer.class, ByteBuffer.allocate(0))

          // io types
          .put(InputStream.class, new ByteArrayInputStream(new byte[0]))
          .put(ByteArrayInputStream.class, new ByteArrayInputStream(new byte[0]))
          .put(Readable.class, new StringReader(""))
          .put(Reader.class, new StringReader(""))
          .put(StringReader.class, new StringReader(""))
          .put(Buffer.class, ByteBuffer.allocate(0))