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

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

{* ../../docs_src/sub_applications/tutorial001_py39.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":

     */
    @Override
    public Iterator<E> iterator() {
        return map.keySet().iterator();
    }

    /**
     * Returns the number of elements in this set (its cardinality).
     *
     * @return the number of elements in this set (its cardinality).
     */
    @Override
    public int size() {
        return map.size();
    }

    /**
     * Returns true if this set contains no elements.
     *

    /**
     * Validate that the constructor masks the supplied value to its
     * lowest 8 bits (NdrShort incorrectly masks to 8 bits even though it's a short).
     */
    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 255, -1, 256, 65535 })
    void constructorMasksValue(int input) {
        NdrShort ns = new NdrShort(input);
        // NdrShort masks to 0xFF (8 bits) in its constructor
        int expected = input & 0xFF;

     * <li>If <code>type</code> is a parameterized type, its raw type is returned.</li>
     * <li>If <code>type</code> is a wildcard type, its (first) upper bound is returned.</li>
     * <li>If <code>type</code> is a type variable and is a key in the given map, its actual type argument is returned.</li>
     * <li>If <code>type</code> is a type variable and is not a key in the given map, its (first) upper bound is returned.</li>

                "org.apache.maven.its.plugins",
                "maven-it-plugin",
                "0.1",
                "compile",
                "jar",
                null,
                new DefaultArtifactHandler("ignore"));
        PluginDescriptor descriptor = new PluginDescriptor();
        descriptor.setGroupId("org.apache.maven.its.plugins");
        descriptor.setArtifactId("maven-it-plugin");

            op.rangeSize(fessConfig.getPagingPageRangeSizeAsInteger());
        }).createPageNumberList());

        return fileConfigList;
    }

    /**
     * Deletes a file configuration and its associated authentication records.
     * This method removes the file configuration from the database and also
     * deletes all related file authentication entries.
     *

    }

    @Test
    void testPluginLoading() throws Exception {
        MavenSession session = createMavenSession(null);
        Plugin plugin = new Plugin();
        plugin.setGroupId("org.apache.maven.its.plugins");
        plugin.setArtifactId("maven-it-plugin");
        plugin.setVersion("0.1");
        PluginDescriptor pluginDescriptor = pluginManager.loadPlugin(

        // Verify field accessibility is restored to its original state
        boolean finalAccessibility = field.canAccess(bean);
        assertEquals(
                initialAccessibility,
                finalAccessibility,
                "Field accessibility should be restored to its original state after setting value");
    }

    @Test

     */
    @Nonnull
    String asString();

    /**
     * Obtain a Stream containing this node and all its descendants.
     *
     * @return a stream containing this node and its descendants
     */
    @Nonnull
    default Stream<Node> stream() {
        return Stream.concat(Stream.of(this), getChildren().stream().flatMap(Node::stream));
    }

    }
    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() {