}

  /**
   * Returns a hash table for the specified keys and values, and ensures that neither keys nor
   * values are null. This method may update {@code alternatingKeysAndValues} if there are duplicate
   * keys. If so, the return value will indicate how many entries are still valid, and will also
   * include a {@link Builder.DuplicateKey} in case duplicate keys are not allowed now or will not

 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs
 * quickly, since the row key is provided. However, {@code column(columnKey).size()} takes longer,

      public Map<Object, Object> create(List<?> keys) {
        return ImmutableMap.copyOf(
            Lists.transform(keys, k -> Maps.immutableEntry(k, "dummy value")));
      }
    },
    BUILDER_PUT_ONE_BY_ONE {
      @Override
      public Map<Object, Object> create(List<?> keys) {
        ImmutableMap.Builder<Object, Object> builder = ImmutableMap.builder();
        for (Object k : keys) {
          builder.put(k, "dummy value");

      return;
    }

    Set<K> keys = map.keySet();
    K key = keys.iterator().next();
    if (supportsRemove) {
      int initialSize = map.size();
      keys.remove(key);
      assertEquals(initialSize - 1, map.size());
      assertFalse(map.containsKey(key));
    } else {
      try {
        keys.remove(key);
        fail("Expected UnsupportedOperationException.");

                for ( KerberosKey key : keys ) {
                    keysByAlgo.put(key.getKeyType(), key);
                }

                KerberosKey serverKey = keysByAlgo.get(encType.getValue().intValue());
                if ( keysByAlgo.isEmpty() || serverKey == null ) {
                    throw new PACDecodingException("Kerberos key not found for eType " + encType.getValue());
                }

    return delegate().getAll(keys);
  }

  @Override
  public V apply(K key) {
    return delegate().apply(key);
  }

  @Override
  public void refresh(K key) {
    delegate().refresh(key);
  }

  /**
   * A simplified version of {@link ForwardingLoadingCache} where subclasses can pass in an already
   * constructed {@link LoadingCache} as the delegate.

      return super.containsEntry(key, value);
    }

    @Override
    public Set<V> get(@Nullable K key) {
      assertTrue(Thread.holdsLock(mutex));
      /* TODO: verify that the Collection is also synchronized? */
      return super.get(key);
    }

    @Override
    public boolean put(K key, V value) {
      assertTrue(Thread.holdsLock(mutex));
      return super.put(key, value);
    }

    for (K key : multimap().keySet()) {
      SortedSet<V> valueSet = (SortedSet<V>) multimap().asMap().get(key);
      assertEquals(multimap().valueComparator(), valueSet.comparator());
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemoveImplementsSortedSet() {
    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();

              }

              @Override
              public @Nullable String put(String key, String value) {
                checkNotNull(key);
                return map.put(key, value);
              }
            };
          }
        },
        "HashMap w/out null keys",
        ALLOWS_NULL_VALUES);
  }

  private static Test testsForHashMapNullValuesForbidden() {

    /**
     * Associates {@code key} with {@code value} in the built map. Duplicate keys are not allowed,
     * and will cause {@link #build} to fail.
     */
    @CanIgnoreReturnValue
    public <T extends B> Builder<B> put(Class<T> key, T value) {
      mapBuilder.put(TypeToken.of(key), value);
      return this;
    }

    /**