// Then
        assertNotNull(appKey, "Application key should not be null");
        assertEquals(16, appKey.length, "Application key should be 16 bytes");
        assertFalse(Arrays.equals(sessionKey, appKey), "Application key should be different from session key");
    }

    @Test
    @DisplayName("Should derive different application keys for different dialects")

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

    }

    /**
     * Returns the application type identifier for this Fess application.
     *
     * @return the application type string "FES"
     */
    @Override
    protected String myAppType() { // for framework
        return APP_TYPE;
    }

    /**
     * Returns the user type identifier for this application.
     *

                                "application/json": {
                                    "schema": {"$ref": "#/components/schemas/Error"}
                                }
                            },
                        },
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },

         */
        OptionalThing<FessUserBean> supply();
    }

    /**
     * The supplier of application type.
     */
    @FunctionalInterface
    public interface AppTypeSupplier {
        /**
         * Supply the application type.
         * @return The application type.
         */
        String supply();
    }

                        "responses": {
                            "200": {
                                "description": "Successful Response",
                                "content": {"application/json": {"schema": {}}},
                            }
                        },
                        "security": [{"OAuth2AuthorizationCodeBearer": []}],
                    }
                },

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

For some types of applications you might want to add dependencies to the whole application.

Similar to the way you can [add `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, you can add them to the `FastAPI` application.

In that case, they will be applied to all the *path operations* in the application:

{* ../../docs_src/dependencies/tutorial012_an_py39.py hl[17] *}

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {