*
 * {@snippet :
 * LoadingCache<Key, Graph> graphs = CacheBuilder.newBuilder()
 *     .maximumSize(10000)
 *     .expireAfterWrite(Duration.ofMinutes(10))
 *     .removalListener(MY_LISTENER)
 *     .build(
 *         new CacheLoader<Key, Graph>() {
 *           public Graph load(Key key) throws AnyException {
 *             return createExpensiveGraph(key);
 *           }
 *         });
 * }
 *

   * equal.
   */
  boolean areEqual();

  /**
   * Returns an unmodifiable map containing the entries from the left map whose keys are not present
   * in the right map.
   */
  Map<K, V> entriesOnlyOnLeft();

  /**
   * Returns an unmodifiable map containing the entries from the right map whose keys are not
   * present in the left map.
   */
  Map<K, V> entriesOnlyOnRight();

  /**

    if (oldNodeForValue != null
        && keyHash == oldNodeForValue.keyHash
        && Objects.equals(key, oldNodeForValue.key)) {
      return key;
    } else if (oldNodeForKey != null && !force) {
      throw new IllegalArgumentException("key already present: " + key);
    }

    if (oldNodeForValue != null) {
      delete(oldNodeForValue);
    }

        assertFalse(result.isPresent());
    }

    @Test
    public void test_ofNullable_withMap() {
        Map<String, Object> testValue = new HashMap<>();
        testValue.put("key1", "value1");
        testValue.put("key2", 42);

        OptionalEntity<Map<String, Object>> result = OptionalUtil.ofNullable(testValue);

        assertNotNull(result);
        assertTrue(result.isPresent());

 * shared resources.
 *
 * @param <K> the most general type of keys this listener can listen for; for example {@code Object}
 *     if any key is acceptable
 * @param <V> the most general type of values this listener can listen for; for example {@code
 *     Object} if any key is acceptable
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
public interface RemovalListener<K, V> {

        }
        return asMap;
      }
    }

    @Override
    public Multiset<K> keys() {
      synchronized (mutex) {
        if (keys == null) {
          keys = multiset(delegate().keys(), mutex);
        }
        return keys;
      }
    }

    @Override
    // A forwarding implementation can't do any better than the underlying object.

     */
    @Test
    public void test_serializeDeserialize_map() {
        Map<String, Object> original = new HashMap<>();
        original.put("key1", "value1");
        original.put("key2", 123);
        original.put("key3", true);

        byte[] serialized = serializer.fromObjectToBinary(original);
        assertNotNull(serialized, "Serialized data should not be null");

   * Multimap#asMap} view determines the ordering in which data is written to the stream.
   *
   * <p>The serialized output consists of the number of distinct keys, and then for each distinct
   * key: the key, the number of values for that key, and the key's values.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMultimap(

        CurlRequest result = request.param("key1", "value1").param("key2", "value2");

        assertSame(request, result); // Fluent API
    }

    @Test
    public void testParamWithNullValue() {
        CurlRequest request = new CurlRequest(Method.GET, "https://example.com");

        CurlRequest result = request.param("key", null);

            Entry<K, V> entry = requireNonNull(entryArray[i]);
            K key = entry.getKey();
            V value = entry.getValue();
            checkEntryNotNull(key, value);
            keys[i] = key;
            values[i] = value;
            checkNoConflict(comparator.compare(prevKey, key) != 0, "key", prevEntry, entry);
            prevKey = key;
          }
        }
        return new ImmutableSortedMap<>(