* (method {@link #add}) are contended across threads, the set of variables may grow dynamically to
 * reduce contention. Method {@link #sum} (or, equivalently, {@link #longValue}) returns the current
 * total combined across the variables maintaining the sum.
 *
 * <p>This class is usually preferable to {@link AtomicLong} when multiple threads update a common

    return toString;
  }

  /** Hasher that updates a checksum. */
  private final class ChecksumHasher extends AbstractByteHasher {
    private final Checksum checksum;

    private ChecksumHasher(Checksum checksum) {
      this.checksum = checkNotNull(checksum);
    }

    @Override
    protected void update(byte b) {
      checksum.update(b);
    }

    @Override

  public static File createTempDir() {
    return TempFileCreator.INSTANCE.createTempDir();
  }

  /**
   * Creates an empty file or updates the last updated timestamp on the same as the unix command of
   * the same name.
   *
   * @param file the file to create or update
   * @throws IOException if an I/O error occurs
   */
  @SuppressWarnings("GoodTime") // reading system time without TimeSource

   * {@code factory}, and the multimap contents are all serializable.
   *
   * <p>The multimap is not threadsafe when any concurrent operations update the multimap, even if
   * {@code map} and the instances generated by {@code factory} are. Concurrent read operations will
   * work correctly. To allow concurrent update operations, wrap the multimap with a call to {@link
   * #synchronizedMultimap}.
   *

   * otherwise-concurrent GC cycle.
   */
  private static final class TaskNonReentrantExecutor extends AtomicReference<RunningState>
      implements Executor, Runnable {

    /**
     * Used to update and read the latestTaskQueue field. Set to null once the runnable has been run
     * or queued.
     */
    @CheckForNull ExecutionSequencer sequencer;

    /**

    return (initialCapacity == UNSET_INT) ? DEFAULT_INITIAL_CAPACITY : initialCapacity;
  }

  /**
   * Guides the allowed concurrency among update operations. Used as a hint for internal sizing. The
   * table is internally partitioned to try to permit the indicated number of concurrent updates
   * without contention. Because assignment of entries to these partitions is not necessarily

  private class TestHasher extends AbstractByteHasher {

    private final ByteArrayOutputStream out = new ByteArrayOutputStream();

    @Override
    protected void update(byte b) {
      out.write(b);
    }

    @Override
    protected void update(byte[] b, int off, int len) {
      out.write(b, off, len);
    }

    byte[] bytes() {
      return out.toByteArray();
    }

        int newNext = getNext(entry, mask);
        if (lastEntryIndex == -1) {
          // we need to update the root link from table[]
          tableSet(table, tableIndex, newNext);
        } else {
          // we need to update the link from the chain
          entries[lastEntryIndex] = maskCombine(entries[lastEntryIndex], newNext, mask);
        }

        return entryIndex;

        int newNext = getNext(entry, mask);
        if (lastEntryIndex == -1) {
          // we need to update the root link from table[]
          tableSet(table, tableIndex, newNext);
        } else {
          // we need to update the link from the chain
          entries[lastEntryIndex] = maskCombine(entries[lastEntryIndex], newNext, mask);
        }

        return entryIndex;

    } finally {
      Thread.currentThread().setContextClassLoader(oldClassLoader);
    }

    Thread.currentThread().setContextClassLoader(NO_ATOMIC_REFERENCE_FIELD_UPDATER);
    try {
      runTestMethod(NO_ATOMIC_REFERENCE_FIELD_UPDATER);
      // TODO(lukes): assert that the logs are full of errors
    } finally {
      Thread.currentThread().setContextClassLoader(oldClassLoader);
    }
  }