* iterable is empty.
   *
   * <p><b>Java 8+ users:</b> the {@code Stream} equivalent to this method is {@code
   * stream.collect(MoreCollectors.toOptional()).orElse(defaultValue)}.
   *
   * @throws IllegalArgumentException if the iterator contains multiple elements
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T getOnlyElement(

   * iterable is empty.
   *
   * <p><b>Java 8+ users:</b> the {@code Stream} equivalent to this method is {@code
   * stream.collect(MoreCollectors.toOptional()).orElse(defaultValue)}.
   *
   * @throws IllegalArgumentException if the iterator contains multiple elements
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T getOnlyElement(

    exclusiveMaximum: Optional[float] = None
    minimum: Optional[float] = None
    exclusiveMinimum: Optional[float] = None
    maxLength: Optional[int] = Field(default=None, ge=0)
    minLength: Optional[int] = Field(default=None, ge=0)
    pattern: Optional[str] = None
    maxItems: Optional[int] = Field(default=None, ge=0)
    minItems: Optional[int] = Field(default=None, ge=0)
    uniqueItems: Optional[bool] = None

    p: Optional[str] = None


@app.get("/model-optional-str")
async def read_model_optional_str(p: Annotated[CookieModelOptionalStr, Cookie()]):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_schema(path: str):
    assert app.openapi()["paths"][path]["get"]["parameters"] == [
        {
            "required": False,

class HeaderModelOptionalListStr(BaseModel):
    p: Optional[list[str]] = None


@app.get("/model-optional-list-str")
async def read_model_optional_list_str(
    p: Annotated[HeaderModelOptionalListStr, Header()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str_schema(path: str):

            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> updateSnapshots() {
        if (commandLine.hasOption(CLIManager.UPDATE_SNAPSHOTS)) {
            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<List<String>> activatedProfiles() {

):
    return {"p": p}


class FormModelOptionalListStr(BaseModel):
    p: Optional[list[str]] = None


@app.post("/model-optional-list-str", operation_id="model_optional_list_str")
async def read_model_optional_list_str(p: Annotated[FormModelOptionalListStr, Form()]):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",

  }

  public void testToJavaUtil_instance() {
    assertEquals(java.util.Optional.empty(), Optional.absent().toJavaUtil());
    assertEquals(java.util.Optional.of("abc"), Optional.of("abc").toJavaUtil());
  }

  @SuppressWarnings("NullOptional")
  public void testFromJavaUtil() {
    assertThat(Optional.fromJavaUtil(null)).isNull();

        gt: Optional[float] = None,
        ge: Optional[float] = None,
        lt: Optional[float] = None,
        le: Optional[float] = None,
        min_length: Optional[int] = None,
        max_length: Optional[int] = None,
        pattern: Optional[str] = None,
        regex: Annotated[
            Optional[str],
            deprecated(
                "Deprecated in FastAPI 0.100.0 and Pydantic v2, use `pattern` instead."

    return {"file_size": len(p) if p else None}


@app.post("/optional-uploadfile", operation_id="optional_uploadfile")
async def read_optional_uploadfile(p: Annotated[Optional[UploadFile], File()] = None):
    return {"file_size": p.size if p else None}


@pytest.mark.parametrize(
    "path",
    [
        "/optional-bytes",
        "/optional-uploadfile",
    ],
)
def test_optional_schema(path: str):
    openapi = app.openapi()