private final List<Thread> hooks = Lists.newArrayList();

    @Override
    synchronized void addShutdownHook(Thread hook) {
      hooks.add(hook);
    }

    synchronized void shutdown() throws InterruptedException {
      for (Thread hook : hooks) {
        hook.start();
      }
      for (Thread hook : hooks) {
        hook.join();
      }
    }
  }

                    // following code, but unfortunately the behavior of logging
                    // is undefined in shutdown hooks.
                    // This is because the logging code installs a shutdown hook of its
                    // own. See Cleaner class inside {@link LogManager}.
                    service.shutdown();

    private final List<Thread> hooks = Lists.newArrayList();

    @Override
    synchronized void addShutdownHook(Thread hook) {
      hooks.add(hook);
    }

    synchronized void shutdown() throws InterruptedException {
      for (Thread hook : hooks) {
        hook.start();
      }
      for (Thread hook : hooks) {
        hook.join();
      }
    }
  }

     * already have to deal with, thanks to DI frameworks that perform field and method injection,
     * frameworks like Android that define post-construct hooks like Activity.onCreate, etc.
     */

    @CheckForNull private ValueSetLink<K, V> predecessorInValueSet;
    @CheckForNull private ValueSetLink<K, V> successorInValueSet;

   * |---------|
   * }</pre>
   */
  private static final SuccessorsFunction<Character> TWO_CYCLES_GRAPH =
      createDirectedGraph("ab", "ac", "bc", "cd", "da");

  /**
   * A tree-shaped graph that looks as follows (all edges are directed facing downwards):
   *
   * <pre>{@code
   *        h
   *       /|\
   *      / | \
   *     /  |  \
   *    d   e   g
   *   /|\      |
   *  / | \     |

 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}
 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>And all the created {@code Book} instances can be tested with:
 *
 * <pre>
 * new ClassSanityTester()
 *     .forAllPublicStaticMethods(Books.class)
 *     .thatReturn(Book.class)

        throw new AssertionError();
    }
  }

  private static int sqrtFloor(int x) {
    // There is no loss of precision in converting an int to a double, according to
    // http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.1.2
    return (int) Math.sqrt(x);
  }

  /**
   * Returns the result of dividing {@code p} by {@code q}, rounding using the specified {@code
   * RoundingMode}.
   *

 * instead of {@code ClassPath}. ClassGraph improves upon {@code ClassPath} in several ways,
 * including addressing many of its limitations. Limitations of {@code ClassPath} include:
 *
 * <ul>
 *   <li>It looks only for files and JARs in URLs available from {@link URLClassLoader} instances or
 *       the {@linkplain ClassLoader#getSystemClassLoader() system class loader}. This means it does

      annotatedTypeExists()
          ? NullnessAnnotationReader.FROM_DECLARATION_AND_TYPE_USE_ANNOTATIONS
          : NullnessAnnotationReader.FROM_DECLARATION_ANNOTATIONS_ONLY;

  /**
   * Looks for declaration nullness annotations and, if supported, type-use nullness annotations.
   *
   * <p>Under Android VMs, the methods for retrieving type-use annotations don't exist. This means

        if (!bits.get(combinedHash % bitSize)) {
          return false;
        }
      }
      return true;
    }
  },
  /**
   * This strategy uses all 128 bits of {@link Hashing#murmur3_128} when hashing. It looks different
   * from the implementation in MURMUR128_MITZ_32 because we're avoiding the multiplication in the
   * loop and doing a (much simpler) += hash2. We're also changing the index to a positive number by