Ticker testTicker = Ticker.systemTicker();
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().ticker(testTicker);
    assertThrows(IllegalStateException.class, () -> builder.ticker(testTicker));
  }

  public void testRemovalListener_setTwice() {
    RemovalListener<Object, Object> testListener = nullRemovalListener();
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().removalListener(testListener);

    Ticker testTicker = Ticker.systemTicker();
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().ticker(testTicker);
    assertThrows(IllegalStateException.class, () -> builder.ticker(testTicker));
  }

  public void testRemovalListener_setTwice() {
    RemovalListener<Object, Object> testListener = nullRemovalListener();
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().removalListener(testListener);

// HEAD requests on an object validates the existence of the object.
// The responses for fetching the object when If-Modified-Since
// and If-Unmodified-Since headers set are validated.
// If-Modified-Since - Return the object only if it has been modified since the specified time, else return a 304 (not modified).

     * </ul>
     *
     * <p>The implementation must ensure that the returned object is functionally
     * equivalent to the input object from the perspective of the Maven model.</p>
     *
     * @param <T> the type of the model object
     * @param object the model object to process
     * @return the processed object (may be the same instance, a pooled instance, or a modified instance)

  public boolean equals(@Nullable Object object) {
    if (object == this) {
      return true;
    }
    if (!(object instanceof Set)) {
      return false;
    }

    Set<?> that = (Set<?>) object;
    if (size() != that.size()) {
      return false;
    } else if (isEmpty()) {
      return true;
    }

    if (SortedIterables.hasSameComparator(comparator, that)) {

    }

    /**
     * Converts the given object to a {@link Date}.
     *
     * @param src
     *            The source object to convert.
     * @return The converted {@link Date}.
     */
    public static Date toDate(final Object src) {
        return toDate(src, null, LocaleUtil.getDefault());
    }

    /**
     * Converts the given object to a {@link Date}.
     *
     * @param src

        .addEqualityGroup(
            entry,
            Tables.<@Nullable Object, @Nullable Object, @Nullable Object>immutableCell(
                null, null, null))
        .addEqualityGroup(
            Tables.<String, @Nullable Object, @Nullable Object>immutableCell("bar", null, null))
        .addEqualityGroup(
            Tables.<@Nullable Object, Integer, @Nullable Object>immutableCell(null, 2, null))
        .addEqualityGroup(

	}
	return iv
}

// SealedKey represents a sealed object key. It can be stored
// at an untrusted location.
type SealedKey struct {
	Key       [64]byte // The encrypted and authenticated object-key.
	IV        [32]byte // The random IV used to encrypt the object-key.
	Algorithm string   // The sealing algorithm used to encrypt the object key.
}

    static Construction<Map<Object, Object>> mapFromKeys(
        Supplier<Map<Object, Object>> mutableSupplier) {
      return keys -> {
        Map<Object, Object> map = mutableSupplier.get();
        for (Object key : keys) {
          map.put(key, new Object());
        }
        return map;
      };
    }

    static Construction<Set<Object>> setFromElements(Supplier<Set<Object>> mutableSupplier) {

    expectArrayContentsInOrder(getOrderedElements(), array);
  }

  public void testToArray_emptyArrayOfObject() {
    Object[] in = new Object[0];
    Object[] array = collection.toArray(in);
    assertEquals(
        "toArray(emptyObject[]) should return an array of type Object",
        Object[].class,
        array.getClass());
    assertEquals("toArray(emptyObject[]).length", getNumElements(), array.length);