* product</a>" of the lists. For example:
   *
   * <pre>{@code
   * Lists.cartesianProduct(ImmutableList.of(
   *     ImmutableList.of(1, 2),
   *     ImmutableList.of("A", "B", "C")))
   * }</pre>
   *
   * <p>returns a list containing six lists in the following order:
   *
   * <ul>
   *   <li>{@code ImmutableList.of(1, "A")}

   *
   * <p>Usage example:
   *
   * <pre>{@code
   * ListenableFuture<Integer> fetchCounterFuture = ...;
   *
   * // Falling back to a zero counter in case an exception happens when
   * // processing the RPC to fetch counters.
   * ListenableFuture<Integer> faultTolerantFuture = Futures.catching(
   *     fetchCounterFuture, FetchException.class, x -> 0, directExecutor());
   * }</pre>
   *

 * factory classes like:
 *
 * <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)

   *
   * <p>Suppose {@code x} is a queue known to contain only strings. The following code can be used
   * to dump the queue into a newly allocated array of {@code String}:
   *
   * <pre>
   *     String[] y = x.toArray(new String[0]);</pre>
   *
   * <p>Note that {@code toArray(new Object[0])} is identical in function to {@code toArray()}.
   *

   * graphs. Example:
   *
   * <pre>{@code
   * static final ImmutableGraph<Country> COUNTRY_ADJACENCY_GRAPH =
   *     GraphBuilder.undirected()
   *         .<Country>immutable()
   *         .putEdge(FRANCE, GERMANY)
   *         .putEdge(FRANCE, BELGIUM)
   *         .putEdge(GERMANY, BELGIUM)
   *         .addNode(ICELAND)
   *         .build();
   * }</pre>
   *

   *
   * <p><b>Note:</b> on Java 8+, it is usually better to use streams. For example:
   *
   * <pre>{@code
   * import static com.google.common.collect.ImmutableMap.toImmutableMap;
   * ...
   * ImmutableMap<Color, String> colorNames =
   *     allColors.stream().collect(toImmutableMap(c -> c, c -> c.toString()));
   * }</pre>
   *
   * <p>Streams provide a more standard and flexible API and the lambdas make it clear what the keys

   *
   * <p><b>Note:</b> on Java 8+, it is usually better to use streams. For example:
   *
   * <pre>{@code
   * import static com.google.common.collect.ImmutableMap.toImmutableMap;
   * ...
   * ImmutableMap<Color, String> colorNames =
   *     allColors.stream().collect(toImmutableMap(c -> c, c -> c.toString()));
   * }</pre>
   *
   * <p>Streams provide a more standard and flexible API and the lambdas make it clear what the keys

   * {@code ClosingFuture}.
   *
   * <p>Example usage:
   *
   * <pre>{@code
   * ClosingFuture<List<Row>> rowsFuture =
   *     queryFuture.transform((closer, result) -> result.getRows(), executor);
   * }</pre>
   *
   * <p>When selecting an executor, note that {@code directExecutor} is dangerous in some cases. See

                  <div class="well">
                      In order to accept this change add the following to <code>${relativePathToMainApiChanges()}</code>:
                    <pre>${prettyPrintJson(acceptanceJson)}</pre>
                  </div>
                </div>
                </p>
                <p>

   *
   * <p>For example,
   *
   * <pre>{@code
   * List<String> badGuys =
   *     Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
   * Function<String, Integer> stringLengthFunction = ...;
   * Multimap<Integer, String> index =
   *     Multimaps.index(badGuys, stringLengthFunction);
   * System.out.println(index);
   * }</pre>
   *
   * <p>prints
   *
   * <pre>{@code