*
     * @return an {@link Optional} containing the map of user properties, or empty if not set
     */
    @Nonnull
    Optional<Map<String, String>> userProperties();

    /**
     * Indicates whether to show the version information and exit.
     *
     * @return an {@link Optional} containing the boolean flag, or empty if not set
     */
    @Nonnull
    Optional<Boolean> showVersionAndExit();

    /**

  }

  private static final Function<Object, Optional<?>> NULLABLE_TO_OPTIONAL =
      new Function<Object, Optional<?>>() {
        @Override
        public Optional<?> apply(@Nullable Object obj) {
          return Optional.fromNullable(obj);
        }
      };

  private static final Function<Optional<?>, @Nullable Object> OPTIONAL_TO_NULLABLE =
      new Function<Optional<?>, @Nullable Object>() {
        @Override

import java.util.List;
import java.util.Optional;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.cli.Options;

/**
 * Defines the options specific to Maven operations.
 * This interface extends the general {@link Options} interface, adding Maven-specific configuration options.
 *

  source:
    type: minio # valid values are "s3" or "minio"
    bucket: mytest
    prefix: object-prefix1 # 'PREFIX' is optional
    # If your source is the 'local' alias specified to 'mc batch start', then the 'endpoint' and 'credentials' fields are optional and can be omitted
    # Either the 'source' or 'remote' *must* be the "local" deployment
#    endpoint: "http://127.0.0.1:9000"

        for (int i = 0; i < size; i++) {
          root = Optional.of(new BinaryNode(rng.nextInt(), root, Optional.<BinaryNode>absent()));
        }
        return root;
      }
    },
    ALL_RIGHT {
      @Override
      Optional<BinaryNode> createTree(int size, Random rng) {
        Optional<BinaryNode> root = Optional.absent();
        for (int i = 0; i < size; i++) {

        for (int i = 0; i < size; i++) {
          root = Optional.of(new BinaryNode(rng.nextInt(), root, Optional.<BinaryNode>absent()));
        }
        return root;
      }
    },
    ALL_RIGHT {
      @Override
      Optional<BinaryNode> createTree(int size, Random rng) {
        Optional<BinaryNode> root = Optional.absent();
        for (int i = 0; i < size; i++) {

   * Point ::= SEQUENCE {
   *   x [0] INTEGER OPTIONAL,
   *   y [1] INTEGER OPTIONAL
   * }
   * ```
   *
   * You may also specify a tag class like [DerHeader.TAG_CLASS_APPLICATION]. The default tag class
   * is [DerHeader.TAG_CLASS_CONTEXT_SPECIFIC].
   *
   * ```
   * Point ::= SEQUENCE {
   *   x [APPLICATION 0] INTEGER OPTIONAL,
   *   y [APPLICATION 1] INTEGER OPTIONAL
   * }
   * ```
   */
  fun withTag(

    throw new IllegalStateException("Optional.get() cannot be called on an absent value");
  }

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

  @SuppressWarnings("unchecked") // safe covariant cast
  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    return (Optional<T>) checkNotNull(secondChoice);
  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = emptiesFirst(comparing(String::length));
    testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required
    Comparator<Optional<String>> unused = emptiesFirst(naturalOrder());

* `skip=20`: da Sie das in der URL gesetzt haben
* `limit=10`: weil das der Defaultwert ist

## Optionale Parameter

Auf die gleiche Weise können Sie optionale Query-Parameter deklarieren, indem Sie deren Defaultwert auf `None` setzen:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

/// check