*     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()
   *         .put('b', "anana")
   *         .putAll('a', "pple", "sparagus")

   *
   * static {
   *     FIRST_LETTER_MULTIMAP = MultimapBuilder.treeKeys().arrayListValues().build();
   *     FIRST_LETTER_MULTIMAP.put('b', "anana");
   *     FIRST_LETTER_MULTIMAP.put('a', "pple");
   *     FIRST_LETTER_MULTIMAP.put('a', "sparagus");
   *     FIRST_LETTER_MULTIMAP.put('c', "arrot");
   *     FIRST_LETTER_MULTIMAP.put('c', "herry");
   * }
   * }
   *

   *
   * static {
   *     FIRST_LETTER_MULTIMAP = MultimapBuilder.treeKeys().arrayListValues().build();
   *     FIRST_LETTER_MULTIMAP.put('b', "anana");
   *     FIRST_LETTER_MULTIMAP.put('a', "pple");
   *     FIRST_LETTER_MULTIMAP.put('a', "sparagus");
   *     FIRST_LETTER_MULTIMAP.put('c', "arrot");
   *     FIRST_LETTER_MULTIMAP.put('c', "herry");
   * }
   * }
   *

   * | `http://host/?`                   | `""`                   |
   * | `http://host/?a=apple&k=key+lime` | `"a=apple&k=key+lime"` |
   * | `http://host/?a=apple&a=apricot`  | `"a=apple&a=apricot"`  |
   * | `http://host/?a=apple&b`          | `"a=apple&b"`          |
   */
  @get:JvmName("encodedQuery")
  val encodedQuery: String?
    get() {

  /**
   * <a
   * href="https://developer.apple.com/library/archive/documentation/UserExperience/Conceptual/PassKit_PG/DistributingPasses.html">Apple
   * Passbook</a>.
   *
   * @since 19.0
   */
  public static final MediaType APPLE_PASSBOOK =
      createConstant(APPLICATION_TYPE, "vnd.apple.pkpass");

  /**

    public void test_entrySet_with_lang_key() {
        Map<String, Object> parentMap = new LinkedHashMap<>();
        DocMap docMap = new DocMap(parentMap);

        docMap.put("zebra", "value1");
        docMap.put("apple", "value2");
        docMap.put("lang", "ja");
        docMap.put("banana", "value3");

        Set<Map.Entry<String, Object>> entrySet = docMap.entrySet();
        assertEquals(4, entrySet.size());

Mas primeiro, vamos verificar alguns pequenos conceitos.

## Está com pressa?

Se você não se importa com qualquer um desses termos e só precisa adicionar segurança com autenticação baseada em usuário e senha _agora_, pule para os próximos capítulos.

## OAuth2

OAuth2 é uma especificação que define várias formas para lidar com autenticação e autorização.

Ela é bastante extensiva na especificação e cobre casos de uso muito complexos.