public void testPut_nullValueSupported() {
    Entry<K, V> nullValueEntry = entry(k3(), null);
    assertNull(
        "putIfAbsent(key, null) should return null",
        getMap().putIfAbsent(nullValueEntry.getKey(), nullValueEntry.getValue()));
    expectAdded(nullValueEntry);
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)

        }

        @Test
        @DisplayName("Should get and set key")
        void testKey() {
            assertNull(referralData.getKey());
            referralData.setKey("cache-key-123");
            assertEquals("cache-key-123", referralData.getKey());
        }

        @Test
        @DisplayName("Should get server")
        void testGetServer() {
            assertNull(referralData.getServer());

     *
     * @param index
     *            the index
     * @return the key at the specified index
     */
    public K getKeyAt(final int index) {
        return getEntryAt(index).getKey();
    }

    /**
     * Returns the {@link java.util.Map.Entry} at the specified index.
     *
     * @param index
     *            the index

  private static <K extends @Nullable Object, V extends @Nullable Object> Entry<K, V> entry(
      K key, V value) {
    return new AbstractMapEntry<K, V>() {
      @Override
      public K getKey() {
        return key;
      }

      @Override
      public V getValue() {
        return value;
      }
    };
  }

		vals = append(vals, foundVal)
		if string(foundKey) != oldKey {
			keys = append(keys, foundKey)
			plSize += len(foundKey)
		} else {
			keys = append(keys, []byte(newKey))
			plSize += len(newKey)
			found = true
		}
	}
	// If not found, just return.
	if !found {
		return false
	}

	// Reserialize...
	x.serialize(plSize, keys, vals)
	return true
}

        if (this.options != null) {
            for (final Entry<String, Object> entry : this.options.entrySet()) {
                ret.append(",").append(entry.getKey()).append("=").append(entry.getValue());
            }
        }
        ret.append("]");
        return ret.toString();
    }

            return size;
        }
        if (obj instanceof Map<?, ?>) {
            long size = 0;
            for (final Map.Entry<?, ?> entry : ((Map<?, ?>) obj).entrySet()) {
                size += sizeOf(entry.getKey());
                size += sizeOf(entry.getValue());
            }
            return size;
        }
        return 16L;
    }

                    for (Object object : elements) {
                      Entry<Class, Impl> entry = (Entry<Class, Impl>) object;
                      map.putInstance(entry.getKey(), entry.getValue());
                    }
                    return (Map) map;
                  }
                })
            .named("MutableClassToInstanceMap")
            .withFeatures(

          Map.Entry<E, Integer> mapEntry = backingEntries.next();
          return new Multisets.AbstractEntry<E>() {
            @Override
            public E getElement() {
              return mapEntry.getKey();
            }

            @Override
            public int getCount() {
              Integer frequency = backingMap.get(getElement());
              return (frequency == null) ? 0 : frequency;

            List<Plugin> plugins = build.getPlugins();
            Map<Object, Plugin> normalized = new LinkedHashMap<>(plugins.size() * 2);

            for (Plugin plugin : plugins) {
                Object key = plugin.getKey();
                Plugin first = normalized.get(key);
                if (first != null) {
                    merger.mergePlugin(plugin, first);
                }
                normalized.put(key, plugin);