Pydantic has a special behavior when you use `Optional` or `Union[Something, None]` without a default value, you can read more about it in the Pydantic docs about <a href="https://docs.pydantic.dev/2.3/usage/models/#required-fields" class="external-link" target="_blank">Required Optional fields</a>.

///

## Type Hints with Metadata Annotations

                    },
                    "summary": "Read Item",
                    "operationId": "read_item_items__item_id__get",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "Item Id", "type": "integer"},
                            "name": "item_id",
                            "in": "path",
                        }
                    ],

                "get": {
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": IsDict(
                                {
                                    "title": "X-Token",
                                    "anyOf": [

 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

public class MapPutIfAbsentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutIfAbsent_supportedAbsent() {
    assertNull(
        "putIfAbsent(notPresent, value) should return null", getMap().putIfAbsent(k3(), v3()));
    expectAdded(e3());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutIfAbsent_supportedPresent() {
    assertEquals(

 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

{!> ../../docs_src/path_params_numeric_validations/tutorial001.py!}
```

////

/// note

A path parameter is always required as it has to be part of the path. Even if you declared it with `None` or set a default value, it would not affect anything, it would still be always required.

///

## Order the parameters as you need

/// tip

This is probably not as important or necessary if you use `Annotated`.

    }
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testGetOrDefault_nonNullWhenNullContained() {
    initMapWithNullKey();
    assertEquals(
        "getOrDefault(absent, default) should return default",
        v3(),
        getMap().getOrDefault(k3(), v3()));
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)

 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.