default void interpolate(
            @Nonnull Map<String, String> map, @Nullable UnaryOperator<String> callback, boolean defaultsToEmpty) {
        interpolate(map, callback, null, defaultsToEmpty);
    }

    /**
     * Interpolates the values in the given map using the provided callback function.
     *
     * @param map The map containing key-value pairs to be interpolated.

   * Integer.MAX_VALUE} elements, returns {@code Integer.MAX_VALUE}.
   */
  public int size() {
    return map.size();
  }

  /** Returns {@code true} if this map contains no key-value mappings. */
  public boolean isEmpty() {
    return map.isEmpty();
  }

  /**

            concreteImplementation.setKey(key);
            assertEquals(key, concreteImplementation.getKey());
        }

        @Test
        @DisplayName("Should set cache map")
        void testSetCacheMap() {
            Map<String, DfsReferralDataInternal> cacheMap = new HashMap<>();

            // Test with mock
            doNothing().when(mockReferralData).setCacheMap(cacheMap);

  }

  public void testEmptyMap() {
    Map<Character, String> map = ImmutableMap.of();
    ArrayBasedEscaperMap fem = ArrayBasedEscaperMap.create(map);
    // Non-null array of zero length.
    assertThat(fem.getReplacementArray()).isEmpty();
  }

  public void testMapLength() {
    Map<Character, String> map =
        ImmutableMap.of(
            'a', "first",
            'z', "last");

            new TestStringMapGenerator() {
              @Override
              protected Map<String, String> create(Entry<String, String>[] entries) {
                Map<String, String> map = populate(new HashMap<String, String>(), entries);
                return Collections.checkedMap(map, String.class, String.class);
              }
            })
        .named("checkedMap/HashMap")
        .withFeatures(

        hoge.setA("A");
        hoge.setB(true);
        hoge.setC(3);
        final Map<String, Object> map = newHashMap();
        BeanUtil.copyBeanToMap(hoge, map);
        assertThat(map, is(notNullValue()));
        assertThat(map.get("a"), is((Object) "A"));
        assertThat(map.get("b"), is((Object) true));
        assertThat(map.get("c"), is((Object) 3));
    }

    /**
     * @throws Exception
     */

        dataStoreParams.put("key3", null);

        Map<String, Object> map = dataStoreParams.asMap();

        assertNotNull(map);
        assertEquals(3, map.size());
        assertEquals("value1", map.get("key1"));
        assertEquals(123, map.get("key2"));
        assertNull(map.get("key3"));

        // Verify that returned map is a copy
        map.put("key4", "value4");

    // keeping parsed request parameters, normal texts or uploaded files
    // keys are requested parameter names (treated as field name here)
    protected Map<String, Object> elementsAll; // lazy-loaded, then after not null
    protected Map<String, MultipartFormFile> elementsFile; // me too
    protected Map<String, String[]> elementsText; // me too

    // ===================================================================================

    }

    private ParamMap<Object, Object> createCamelMap() {
        final Map<Object, Object> map = new HashMap<>();
        map.put("aaa", "111");
        map.put("aaaBbb", "222");
        map.put("aaaBbbCcc", "333");
        map.put("ccc.ddd", "444");
        return new ParamMap<>(map);
    }

    public void test_snake_get() {
        Map<Object, Object> paramMap = createSnakeMap();

        assertNull(paramMap.get("xxx"));

    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableSortedMap.of("a", holderA, "b", holderB);
    holderA.value = 3;
    assertTrue(map.entrySet().contains(immutableEntry("a", new IntHolder(3))));
    Map<String, Integer> intMap = ImmutableSortedMap.of("a", 3, "b", 2);
    assertEquals(intMap.hashCode(), map.entrySet().hashCode());
    assertEquals(intMap.hashCode(), map.hashCode());
  }

  @J2ktIncompatible