* buildOrThrow() will still throw as if the duplicates had not been eliminated. And the exception
   * message must mention two values that were associated with the duplicate key in two different
   * calls to Builder.put (though we don't really care *which* two values if there were more than
   * two). These considerations lead us to have a field of type DuplicateKey in the Builder, which

    Runnable submittedTask;
    long oldRunCount;
    synchronized (queue) {
      // If the worker is already running (or execute() on the delegate returned successfully, and
      // the worker has yet to start) then we don't need to start the worker.
      if (workerRunningState == RUNNING || workerRunningState == QUEUED) {
        queue.add(task);
        return;
      }

      oldRunCount = workerRunCount;

    }

    void calculateNextPermutation() {
      int j = findNextJ();
      if (j == -1) {
        nextPermutation = null;
        return;
      }
      /*
       * requireNonNull is safe because we don't clear nextPermutation until we're done calling this
       * method.
       */
      requireNonNull(nextPermutation);

      int l = findNextL(j);
      Collections.swap(nextPermutation, j, l);

    private final Joiner joiner;
    private final String keyValueSeparator;

    private MapJoiner(Joiner joiner, String keyValueSeparator) {
      this.joiner = joiner; // only "this" is ever passed, so don't checkNotNull
      this.keyValueSeparator = checkNotNull(keyValueSeparator);
    }

    /**
     * Appends the string representation of each entry of {@code map}, using the previously

   * cannot implement that interface in source code in a way that will compile on both Java 7 and
   * Java 8. If we include the {@code getAnnotatedBounds()} method then its return type means it
   * won't compile on Java 7, while if we don't include the method then the compiler will complain
   * that an abstract method is unimplemented. So instead we use a dynamic proxy to get an

          queuedExecutor.execute(queuedTask);
        }
      } finally {
        // Null out the thread field, so that we don't leak a reference to Thread, and so that
        // future `thread == currentThread()` calls from this thread don't incorrectly queue instead
        // of executing. Don't null out the latestTaskQueue field, because the work done here

  public void testNullPointers() {
    /*
     * Don't bother testing: Preconditions defines a bunch of methods that accept a template (or
     * even entire message) that simultaneously:
     *
     * - _shouldn't_ be null, so we don't annotate it with @Nullable
     *
     * - _can_ be null without causing a runtime failure (because we don't want the interesting

     * Luckily, our nullness checker is smart enough to realize that `convert` has @PolyNull-like
     * behavior, so it knows that `convert(a)` returns a non-nullable value, and we don't need to
     * perform even a cast, much less a runtime check.
     *
     * All that said, don't forget that everyone should call converter.convert() instead of
     * converter.apply(), anyway. If clients use only converter.convert(), then their nullness

  // In the backport, we don't have those cases and thus don't need this suppression.
  // We keep it to minimize diffs.
  @SuppressWarnings("unchecked")
  public static <E> ImmutableSet<E> copyOf(Collection<? extends E> elements) {
    /*
     * TODO(lowasser): consider checking for ImmutableAsList here
     * TODO(lowasser): consider checking for Multiset here
     */

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    // don't see absent values now that count > 0
    assertNull(segment.get(new Object(), hash));

    // null key
    InternalEntry<Object, Object, ?> nullEntry = segment.newEntryForTesting(null, hash, entry);