return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);
    return this;
  }

  @Override

  }

  @CheckForNull private T next;

  @CheckForNull
  protected abstract T computeNext();

  @CanIgnoreReturnValue
  @CheckForNull
  protected final T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override
  public final boolean hasNext() {
    checkState(state != State.FAILED);
    switch (state) {
      case DONE:
        return false;
      case READY:
        return true;

                    final Properties properties = new Properties();
                    if (is != null) {
                        try (InputStream in = is) {
                            properties.load(in);
                        }
                    }
                    String impl = properties.getProperty(slf4jBinding);
                    if (impl != null) {
                        return (Slf4jConfiguration) Class.forName(impl).newInstance();

    }

    override fun obtain(): String? = parameters.run {

        val buildTimestampFromReceipt = buildTimestampFromBuildReceipt.orNull
        if (buildTimestampFromReceipt != null) {
            println("Using timestamp from incoming build receipt: $buildTimestampFromReceipt")
            return buildTimestampFromReceipt
        }

        this.metaData = propertyMetaData
        id = "${referringClass.className}:$name"
        this.comment = comment
        if (additionalValues == null) {
            throw new NullPointerException("additionalValues constructor var is null for referringClass: $referringClass")
        }
        this.additionalValues = additionalValues
    }

    PropertyDoc forClass(ClassDoc referringClass) {

    @Test
    void testMirrorLayoutConsideredForMatching() {
        ArtifactRepository repo = getRepo("a");

        Mirror mirrorA = newMirror("a", "a", null, "http://a");
        Mirror mirrorB = newMirror("b", "a", "p2", "http://b");

        Mirror mirrorC = newMirror("c", "*", null, "http://c");
        Mirror mirrorD = newMirror("d", "*", "p2", "http://d");

    @CheckForNull
    private Iterator<? extends Iterator<? extends T>> getTopMetaIterator() {
      while (topMetaIterator == null || !topMetaIterator.hasNext()) {
        if (metaIterators != null && !metaIterators.isEmpty()) {
          topMetaIterator = metaIterators.removeFirst();
        } else {
          return null;
        }
      }

    toPut.put(null, 1);
    ImmutableListMultimap.Builder<String, Integer> builder = ImmutableListMultimap.builder();
    assertThrows(NullPointerException.class, () -> builder.put(null, 1));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, Arrays.asList(1, 2, 3)));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, 1, 2, 3));
    assertThrows(

          },
          "mappings": [],
          "thresholds": {
            "mode": "absolute",
            "steps": [
              {
                "color": "green",
                "value": null
              },
              {
                "color": "red",
                "value": 80
              }
            ]
          },
          "unit": "short"
        },
        "overrides": []

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

Isso significa que ele **sempre terá um valor**, só que às vezes o valor pode ser `None` (ou `null` em termos de JSON).