String message = "Serializable SSO exception";
        Exception cause = new RuntimeException("Serializable cause");
        SsoLoginException originalException = new SsoLoginException(message, cause);

        // Serialize the exception
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(originalException);
        oos.close();

```

</div>

Então, vá para a interface `/docs`, você verá que o **FastAPI** está usando esses **modelos** para **documentar** a API, e ele também os usará para **serializar** e **validar** os dados.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Atualizar o App com Múltiplos Modelos

  private void readObject(ObjectInputStream stream) throws InvalidObjectException {
    throw new InvalidObjectException("Use SerializedForm");
  }

  /*
   * This class is used to serialize ImmutableEnumSet instances.
   */
  @J2ktIncompatible // serialization
  private static final class EnumSerializedForm<E extends Enum<E>> implements Serializable {
    final EnumSet<E> delegate;

    `com.google.guava:failureaccess:1.0.3`. It also has
    [some annotation-only dependencies][guava-deps], which we discuss in more
    detail at that link.

4.  Serialized forms of ALL objects are subject to change unless noted
    otherwise. Do not persist these and assume they can be read by a future
    version of the library.

    return new SerializedForm<>(delegate());
  }

    private void readObject(ObjectInputStream stream) throws InvalidObjectException {
    throw new InvalidObjectException("Use SerializedForm");
  }

  /** Serialized form of the map, to avoid serializing the constraint. */
  private static final class SerializedForm<B extends @Nullable Object> implements Serializable {
    private final Map<Class<? extends @NonNull B>, B> backingMap;

  }

  /** Returns the value of this {@code AtomicDouble} as a {@code double}. */
  @Override
  public double doubleValue() {
    return get();
  }

  /**
   * Saves the state to a stream (that is, serializes it).
   *
   * @serialData The current value is emitted (a {@code double}).
   */
  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();

    s.writeDouble(get());

        byte[] tokenArray = new byte[] { 1, 2, 3 };
        byte[] mic = new byte[] { 9, 9, 9 };
        NegTokenTarg original = new NegTokenTarg(NegTokenTarg.ACCEPT_COMPLETED, mech, tokenArray, mic);

        // Act – serialise and parse back
        byte[] bytes = original.toByteArray();
        NegTokenTarg roundTrip = new NegTokenTarg(bytes);

        // Assert – all getters match the original values

 * {@link #writeTo} and {@link #readFrom} methods. Both serialized forms will continue to be
 * supported by future versions of this library. However, serial forms generated by newer versions
 * of the code may not be readable by older versions of the code (e.g., a serialized Bloom filter
 * generated today may <i>not</i> be readable by a binary that was compiled 6 months ago).
 *

     * @throws Exception
     */
    @Test
    public void testSerialize() throws Exception {
        list.addLast("1");
        list.addLast("2");
        list.addLast("3");
        assertThat(SerializeUtil.serialize(list), is(notNullValue()));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testSet() throws Exception {
        list.addLast("1");
        list.addLast("2");

        assertFalse(user.refresh());
        assertEquals(1, user.getRefreshCount());
    }

    public void test_serialization() {
        // Test that implementations can be serialized
        FessUser user = new TestFessUser("testuser", new String[] { "role1", "role2" }, new String[] { "group1", "group2" },
                new String[] { "perm1", "perm2" });