}

    /**
     * Test Rule with null ResponseData
     */
    public void test_matchWithNullResponseData() {
        ConfigurableRule rule = new ConfigurableRule();
        rule.setRuleId("nullTest");
        rule.setResponseProcessor(new TestResponseProcessor("nullProcessor"));

        // Should handle null gracefully
        assertFalse(rule.match(null));
    }

    /**

   * nullText} for any provided null elements.
   */
  public Joiner useForNull(String nullText) {
    checkNotNull(nullText);
    return new Joiner(this) {
      @Override
      CharSequence toString(@Nullable Object part) {
        return (part == null) ? nullText : Joiner.this.toString(part);
      }

      @Override

   * nullText} for any provided null elements.
   */
  public Joiner useForNull(String nullText) {
    checkNotNull(nullText);
    return new Joiner(this) {
      @Override
      CharSequence toString(@Nullable Object part) {
        return (part == null) ? nullText : Joiner.this.toString(part);
      }

      @Override

@GwtCompatible
final class NullnessCasts {
  /**
   * Accepts a {@code @Nullable T} and returns a plain {@code T}, without performing any check that
   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null

@GwtCompatible
final class NullnessCasts {
  /**
   * Accepts a {@code @Nullable T} and returns a plain {@code T}, without performing any check that
   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null

          <item index="10" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableDecl" />
          <item index="11" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableType" />
          <item index="12" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.Nullable" />

            if (builder == null) {
                throw new IOException("Builder is null");
            }
            builder.startObject();
            builder.field("null_test", "value");
            builder.endObject();
            return builder;
        };

        // This should handle any IOException gracefully

   *
   * @throws NullPointerException if the first element is null; if this is a possibility, use {@code
   *     iterator().next()} or {@link Iterables#getFirst} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> first() {
    Iterator<E> iterator = getDelegate().iterator();
    return iterator.hasNext() ? Optional.of(iterator.next()) : Optional.absent();

   *
   * @throws NullPointerException if the first element is null; if this is a possibility, use {@code
   *     iterator().next()} or {@link Iterables#getFirst} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> first() {
    Iterator<E> iterator = getDelegate().iterator();
    return iterator.hasNext() ? Optional.of(iterator.next()) : Optional.absent();

  }

  public void testCallableStartsAfterFirstFutureCompletes() {
    @SuppressWarnings({"unused", "nullness"})
    Future<?> possiblyIgnoredError = serializer.submitAsync(firstCallable, directExecutor());
    TestCallable secondCallable = new TestCallable(Futures.<Void>immediateFuture(null));
    @SuppressWarnings({"unused", "nullness"})
    Future<?> possiblyIgnoredError1 = serializer.submitAsync(secondCallable, directExecutor());