****
**In this section, you will:**

- Understand Multi-Project builds
- Understand Composite Builds
- Add a subproject to your Build
- Add a build to your Build
****

[[part3_begin]]
== Step 0. Before you Begin

1. You initialized your Java app in <<partr1_gradle_init.adoc#part1_begin,part 1>>.
2. You understand the Gradle Build Lifecycle from <<partr2_build_lifecycle.adoc#part2_begin,part 2>>.

Pour expliquer la différence, voici une histoire de burgers :

#### Burgers concurrents

Vous amenez votre crush 😍 dans votre fast food 🍔 favori, et faites la queue pendant que le serveur 💁 prend les commandes des personnes devant vous.

Puis vient votre tour, vous commandez alors 2 magnifiques burgers 🍔 pour votre crush 😍 et vous.

Vous payez 💸.

FastAPI will use this return type to:

* **Validate** the returned data.
    * If the data is invalid (e.g. you are missing a field), it means that *your* app code is broken, not returning what it should, and it will return a server error instead of returning incorrect data. This way you and your clients can be certain that they will receive the data and the data shape expected.
* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.

## The main `FastAPI`

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI`

You import and create a `FastAPI` class as normally.

In the output, there's a line with something like:

```hl_lines="4"
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

That line shows the URL where your app is being served, in your local machine.

### Check it

Open your browser at <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

You will see the JSON response as:

```JSON
{"message": "Hello World"}

You must agree to the terms of [Developer Certificate of Origin](https://developercertificate.org/) by signing off your commits. We automatically verify that all commit messages contain a `Signed-off-by:` line with your email address. We can only accept PRs that have all commits signed off.

If you didn't sign off your commits before creating the pull request, you can fix that after the fact.

To sign off a single commit:

You can view the latest and full list of accepted tags in [`doclint/HtmlTag.java`](https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/swing/text/html/HTML.Tag.html) for your JDK of choice.

Attempt to limit your usage of HTML to: `"a", "h1", "h2", "h3", "h4", "em", "li", "ol", "p", "ul"`.

Some HTML element types allow authors to omit end tags: `<p>` and `<li>`.

### 1.1.3 Paragraphs

    Hug a contribué à inspirer **FastAPI** pour utiliser les type hints Python
    pour déclarer les paramètres, et pour générer automatiquement un schéma définissant l'API.

    Hug a inspiré **FastAPI** pour déclarer un paramètre `response` dans les fonctions pour définir les en-têtes et les cookies.

----

We observe that only a small number of help tasks are available at the moment.
This is because the core of Gradle only provides tasks that analyze your build.
Other tasks, such as the those that build your project or compile your code, are added by plugins.

Let's explore this by adding the <<base_plugin.adoc#base_plugin,Gradle core `base` plugin>> to the `app` build script:

====
[.multi-language-sample]

WARNING: You will have to accept the terms of service to use Build Scans.

You will need to activate the Build Scan by using your email:

image::tutorial/build-scan-prompt.png[]

You will receive the final link to the scan in your inbox which should look as follows:

image::tutorial/build-scan-results.png[]