*       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

 *     Object}, or use {@code @Nullable Object} to allow null values.
 * @since 2.0
 */
@DoNotMock("Use ImmutableClassToInstanceMap or MutableClassToInstanceMap")
@GwtCompatible
public interface ClassToInstanceMap<B extends @Nullable Object>
    extends Map<Class<? extends @NonNull B>, B> {
  /**
   * Returns the value the specified class is mapped to, or {@code null} if no entry for this class

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless

        versioning.setLastUpdatedTimestamp(timestamp);

        if (recessive.getVersioning() != null) {
            if (versioning.getLatest() == null) {
                versioning.setLatest(recessive.getVersioning().getLatest());
            }
            if (versioning.getRelease() == null) {
                versioning.setRelease(recessive.getVersioning().getRelease());
            }

     *
     * @param o
     *            The object to convert
     * @return The converted {@link Boolean}
     */
    public static Boolean toBoolean(final Object o) {
        return switch (o) {
        case null -> null;
        case Boolean b -> b;
        case Number n -> n.intValue() != 0;
        case String s -> switch (s.toLowerCase()) {
        case "true" -> Boolean.TRUE;
        case "false", "0" -> Boolean.FALSE;

                    final Map<String, Object> source = hit.getSourceAsMap();
                    if (source != null) {
                        docMap.putAll(source);
                    }
                    final Map<String, DocumentField> fields = hit.getFields();
                    if (fields != null) {
                        docMap.putAll(fields.entrySet()
                                .stream()