if (oldValue != 0) {
        int newValue = max(0, oldValue - occurrences);
        if (existingCounter.compareAndSet(oldValue, newValue)) {
          if (newValue == 0) {
            // Just CASed to 0; remove the entry to clean up the map. If the removal fails,
            // another thread has already replaced it with a new counter, which is fine.
            countMap.remove(element, existingCounter);
          }

  }

  public void testCreation_generic() {
    List<String> a = ImmutableList.of("a");
    // only verify that there is no compile warning
    ImmutableList<List<String>> unused = ImmutableList.of(a, a);
  }

  public void testCreation_arrayOfArray() {
    String[] array = new String[] {"a"};
    List<String[]> list = ImmutableList.<String[]>of(array);

    ListeningExecutorService executor = newDirectExecutorService();
    List<Callable<T>> tasks = ImmutableList.of();
    List<? extends Future<?>> unused = executor.invokeAll(tasks);
  }

  public void testListeningDecorator() throws Exception {
    ListeningExecutorService service = listeningDecorator(newDirectExecutorService());

     * whenever they pass `true` for the matching `has*Bound` parameter.
     */
    if (hasLowerBound) {
      int unused =
          comparator.compare(
              uncheckedCastNullableTToT(lowerEndpoint), uncheckedCastNullableTToT(lowerEndpoint));
    }
    if (hasUpperBound) {
      int unused =
          comparator.compare(
              uncheckedCastNullableTToT(upperEndpoint), uncheckedCastNullableTToT(upperEndpoint));

    public void testConstructorWithNull() throws Exception {
        new EnumerationIterator<String>((Enumeration<String>) null);
    }

    /**
     * @throws Exception
     */
    @SuppressWarnings("unused")
    @Test
    public void testIterable() throws Exception {
        final Vector<String> vector = new Vector<String>();
        vector.add("a");
        vector.add("b");
        int count = 0;

  private Class<?> abstractFutureClass;

  @Override
  protected void setUp() throws Exception {
    // Load the "normal" copy of SettableFuture and related classes.
    SettableFuture<?> unused = SettableFuture.create();
    // Hack to load AbstractFuture et. al. in a new classloader so that it re-reads the cancellation
    // cause system property.  This allows us to run with both settings of the property in one jvm

  private Class<?> abstractFutureClass;

  @Override
  protected void setUp() throws Exception {
    // Load the "normal" copy of SettableFuture and related classes.
    SettableFuture<?> unused = SettableFuture.create();
    // Hack to load AbstractFuture et. al. in a new classloader so that it re-reads the cancellation
    // cause system property.  This allows us to run with both settings of the property in one jvm

       * trivially, but it's enough to skip these ones.
       */
      ) {
        continue;
      }
      Class<?> clazz = info.load();
      try {
        Method unused = clazz.getDeclaredMethod("writeReplace");
        continue; // It overrides writeReplace, so it's safe.
      } catch (NoSuchMethodException e) {
        // This is a class whose supertypes we want to examine. We'll do that below.

    return Math.sqrt(populationVariance());
  }

  /**
   * Returns the <a href="http://en.wikipedia.org/wiki/Variance#Sample_variance">unbiased sample
   * variance</a> of the values. If this dataset is a sample drawn from a population, this is an
   * unbiased estimator of the population variance of the population. The count must be greater than
   * one.
   *

      return super.writeReplace();
    }

    // No longer used for new writes, but kept so that old data can still be read.
    @GwtIncompatible // serialization
    @J2ktIncompatible
    @SuppressWarnings("unused")
    private static class SerializedForm<K> implements Serializable {
      final ImmutableMap<K, ?> map;

      SerializedForm(ImmutableMap<K, ?> map) {
        this.map = map;
      }