* to Java development tools, such as the Java compiler and Java runtime
 * environment. This interface allows users to define and configure
 * Java-related toolchains that can be utilized during the build process
 * in Maven.</p>
 *
 * <p>Java toolchains are defined in the Maven toolchains.xml file and can
 * be referenced in the project's POM file. This enables developers to

# Lifespan Events { #lifespan-events }

You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

    @Nonnull
    Optional<Project> getParent();

    /**
     * Returns all profiles defined in this project.
     * <p>
     * This method returns only the profiles defined directly in the current project's POM
     * and does not include profiles from parent projects.
     *
     * @return a non-null, possibly empty list of profiles defined in this project
     * @see Profile
     * @see #getEffectiveProfiles()
     */

 *
 * <p>The {@code Packaging} class is an immutable value object, ensuring that once a packaging type is defined, it cannot be changed.</p>
 *
 * <h2>Standard Packaging Types</h2>
 * <ul>
 *     <li>{@code jar}: Packages the project as a Java Archive (JAR) file.</li>

 isIE from './isIE';\n/**\n * Finds the first parent of an element that has a transformed property defined\n * @method\n * @memberof Popper.Utils\n * @argument {Element} element\n * @returns {Element} first transformed parent or documentElement\n */\n\nexport default function getFixedPositionOffsetParent(element) {\n  // This check is needed to avoid errors in case one of the elements isn't defined for any reason\n   if (!element || !element.parentElement || isIE()) {\n    return document.documentElement;\n...

* `PUT`: to update data.
* `DELETE`: to delete data.

So, in OpenAPI, each of the HTTP methods is called an "operation".

We are going to call them "**operations**" too.

#### Define a *path operation decorator* { #define-a-path-operation-decorator }

{* ../../docs_src/first_steps/tutorial001.py hl[6] *}

The `@app.get("/")` tells **FastAPI** that the function right below is in charge of handling requests that go to:

    // vol. 2, Knuth, 4.2.2, (16) to the two-variable case. We have two value series x_i and y_i.
    // We define the arithmetic means X_n = 1/n \sum_{i=1}^n x_i, and Y_n = 1/n \sum_{i=1}^n y_i.
    // We also define the sum of the products of the differences from the means
    //           C_n = \sum_{i=1}^n x_i y_i - n X_n Y_n
    // for all n >= 1. Then for all n > 1:

**FastAPI** will know that it can use this dependency to define a "security scheme" in the OpenAPI schema (and the automatic API docs).

/// info | Technical Details

     * defined as:
     *
     * {@snippet :
     * ((element == null) ? 0 : element.hashCode()) ^ count
     * }
     */
    @Override
    int hashCode();

    /**
     * Returns the canonical string representation of this entry, defined as follows. If the count

  public static final MediaType WEBM_AUDIO = createConstant(AUDIO_TYPE, "webm");

  /**
   * L16 audio, as defined by <a href="https://tools.ietf.org/html/rfc2586">RFC 2586</a>.
   *
   * @since 24.1
   */
  public static final MediaType L16_AUDIO = createConstant(AUDIO_TYPE, "l16");

  /**
   * L24 audio, as defined by <a href="https://tools.ietf.org/html/rfc3190">RFC 3190</a>.
   *
   * @since 20.0
   */