### Top-level application { #top-level-application }

First, create the main, top-level, **FastAPI** application, and its *path operations*:

{* ../../docs_src/sub_applications/tutorial001_py310.py hl[3, 6:8] *}

### Sub-application { #sub-application }

Then, create your sub-application, and its *path operations*.

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

The history of **FastAPI** is in great part the history of its predecessors.

As said in the section [Alternatives](alternatives.md):

<blockquote markdown="1">

**FastAPI** wouldn't exist if not for the previous work of others.

There have been many tools created before that have helped inspire its creation.

Use its [builder][handshake_certificates_builder] to define which certificates the HTTPS server
returns to its clients. The returned instance can create an `SSLSocketFactory` that implements this
policy:

```java
HandshakeCertificates serverCertificates = new HandshakeCertificates.Builder()
    .heldCertificate(localhostCertificate)
    .build();
MockWebServer server = new MockWebServer();

    }
    copyIntoArray(other, 0);
    return other;
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  @Nullable Object @Nullable [] internalArray() {
    return null;
  }

  /**
   * If this collection is backed by an array of its elements in insertion order, returns the offset
   * where this collection's elements start.
   */
  int internalArrayStart() {

import java.util.PriorityQueue;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * A double-ended priority queue, which provides constant-time access to both its least element and
 * its greatest element, as determined by the queue's specified comparator. If no comparator is
 * given at creation time, the natural order of elements is used. If no maximum size is given at

    }
    copyIntoArray(other, 0);
    return other;
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  Object @Nullable [] internalArray() {
    return null;
  }

  /**
   * If this collection is backed by an array of its elements in insertion order, returns the offset
   * where this collection's elements start.
   */
  int internalArrayStart() {

@NullUnmarked
@GwtIncompatible
@J2ktIncompatible
public class ListenableFutureTest extends TestCase {
  public void testNoNewApis() throws Exception {
    assertWithMessage(
            "Do not add new methods to ListenableFuture. Its API needs to continue to match the"
                + " version we released in a separate artifact com.google.guava:listenablefuture.")
        .that(ListenableFuture.class.getDeclaredMethods())
        .asList()

// value. Unlike new, make's return type is the same as the type of its
// argument, not a pointer to it. The specification of the result depends on
// the type:
//
//   - Slice: The size specifies the length. The capacity of the slice is
//     equal to its length. A second integer argument may be provided to
//     specify a different capacity; it must be no smaller than the

# Calls

The HTTP client’s job is to accept your request and produce its response. This is simple in theory but it gets tricky in practice.

## [Requests](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-request/)

Each HTTP request contains a URL, a method (like `GET` or `POST`), and a list of headers. Requests may also contain a body: a data stream of a specific content type.

## [Responses](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-response/)

}

/**
 * To other developers, if you are using this method above, please use the following syntax.
 * By default this method does NOT execute ITs anymore, just "install".
 *
 * mavenBuild("<jdk>", "<profiles> <goals> <plugins> <properties>"
 *
 * @param jdk the jdk tool name (in jenkins) to use for this build
 * @param extraArgs extra command line args
 */