"anyOf": [{"type": "string"}, {"type": "null"}],
                        },
                        "price": {"title": "Price", "type": "number"},
                        "tax": {
                            "title": "Tax",
                            "anyOf": [{"type": "number"}, {"type": "null"}],
                        },
                        "tags": {

        stack.addFirst(document.createElement("root"));
    }

    List<Element> getElements() {
        List<Element> elements = new ArrayList<Element>();
        for (Node node = stack.getLast().getFirstChild(); node != null; node = node.getNextSibling()) {
            elements.add((Element) node);
        }
        return elements;
    }

    public void appendChild(String text) {
        appendChild(document.createTextNode(text));

    }

    @Override
    public CacheRecord put(Key key, ClassRealm pluginRealm, List<Artifact> pluginArtifacts) {
        Objects.requireNonNull(pluginRealm, "pluginRealm cannot be null");
        Objects.requireNonNull(pluginArtifacts, "pluginArtifacts cannot be null");

        if (cache.containsKey(key)) {
            throw new IllegalStateException("Duplicate plugin realm for plugin " + key);
        }

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

Das bedeutet, dass es **immer einen Wert** hat, der Wert kann jedoch manchmal `None` sein (oder `null` in JSON).

                            "in": "query",
                            "required": False,
                            "schema": {
                                "anyOf": [{"type": "string"}, {"type": "null"}],
                                "examples": [
                                    "json_schema_query1",
                                    "json_schema_query2",
                                ],

        }

        ModelObjectProcessor processor = ProcessorHolder.CACHED_PROCESSOR.get();
        if (processor == null) {
            processor = loadProcessor();
            ProcessorHolder.CACHED_PROCESSOR.compareAndSet(null, processor);
            processor = ProcessorHolder.CACHED_PROCESSOR.get();
        }
        return processor.process(object);
    }

    /**

                MavenSession session,
                RepositorySystem repositorySystem,
                List<org.apache.maven.api.RemoteRepository> repositories) {
            super(session, repositorySystem, repositories, null, null, null);
        }

        @Override
        protected Session newSession(
                MavenSession mavenSession, List<org.apache.maven.api.RemoteRepository> repositories) {

     * @throws NullPointerException if session or source is null
     */
    @Nonnull
    static ProjectBuilderRequest build(@Nonnull Session session, @Nonnull Source source) {
        return builder()
                .session(requireNonNull(session, "session cannot be null"))
                .source(requireNonNull(source, "source cannot be null"))
                .build();
    }

    /**

     *
     * @param model The model whose build plugin configuration should be expanded, must not be <code>null</code>.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */
    void expandPluginConfiguration(Model model, ModelBuildingRequest request, ModelProblemCollector problems);

        StringBuilder repos = new StringBuilder("[");

        if (localRepository != null) {
            repos.append(localRepository.getId())
                    .append(" (")
                    .append(localRepository.getBasedir())
                    .append(")");
        }

        if (remoteRepositories != null && !remoteRepositories.isEmpty()) {
            for (RemoteRepository repository : remoteRepositories) {