*/
    public static <KEY, VALUE> Maps<KEY, VALUE> hashMap(final KEY key, final VALUE value) {
        return new Maps<>(new HashMap<KEY, VALUE>()).$(key, value);
    }

    /**
     * Returns a {@literal Maps} for constructing a {@link Hashtable} with the specified key and value.
     *
     * @param <KEY> the key type of the <code>Map</code>

        if (valueItr == null) {
          valueIterators.put(key, valueItr = sampleValuesIterator());
        }
        entries[i] = mapEntry(key, valueItr.next());
      }
      return multimapGenerator.create((Object[]) entries).keys();
    }

    private Iterator<V> sampleValuesIterator() {
      return ((TestMultimapGenerator<K, V, M>) multimapGenerator.getInnerGenerator())
          .sampleValues()

    }

    /** Case 5: Overwrite processing for multiple fields, existing overwrite keys are also properly removed */
    public void test_mergeResponseData_multipleOverwrite() {
        Map<String, Object> dataMap = new HashMap<>();
        // Case where the initial dataMap also contains overwrite keys
        dataMap.put("m", "M0");
        dataMap.put("n.overwrite", "N0_old");

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
  }

   * key. When a key-value pair is added to a multimap that didn't previously
   * contain any values for that key, a new collection generated by
   * createCollection is added to the map. That same collection instance
   * remains in the map as long as the multimap has any values for the key. If
   * all values for the key are removed, the key and collection are removed
   * from the map.
   *

    CacheLoader<Integer, String> recursiveLoader =
        new CacheLoader<Integer, String>() {
          @Override
          public String load(Integer key) {
            if (key > 0) {
              return key + ", " + cacheRef.get().getUnchecked(key - 1);
            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =

      assertEquals(property.key() + "=" + property.value(), property.toString());
    }
  }

  public void testNoNullValues() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      // Even though the contract in System.getProperties() specifies that a value will exist for
      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {

	// ErrDuplicatedKey occurs when there is a unique key constraint violation
	ErrDuplicatedKey = errors.New("duplicated key not allowed")
	// ErrForeignKeyViolated occurs when there is a foreign key constraint violation
	ErrForeignKeyViolated = errors.New("violates foreign key constraint")
	// ErrCheckConstraintViolated occurs when there is a check constraint violation

           * We assign these to variables before calling checkNotNull to work around a bug in our
           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);
          accum.put(
              checkNotNull(key, "Null key for input %s", t),
              checkNotNull(newValue, "Null value for input %s", t));
        },
        EnumMapAccumulator::combine,