* @since 4.0.0
 */
@Experimental
@Immutable
@SuppressWarnings("checkstyle:InterfaceIsType")
public interface Language extends ExtensibleEnum {

    /**
     * The "none" language. It is not versioned, family is same to itself, and compatible with itself only.
     * In turn, every {@link Language} implementation must be compatible with {@code NONE} language.
     */
    Language NONE = language("none");

    /**

/**
 * Provides access to the contents of a POM independently of the backing store (e.g. file system, database, memory).
 * <p>
 * This interface does not support loading of parent POM(s) from the same backing store, integrators are strongly
 * encouraged to implement {@link ModelSource2} instead of implementing this interface directly.
 *
 * @see ModelSource2
 * @deprecated instead use {@link Source}
 */
@Deprecated

     *
     * @param callback The original function to be memoized. It takes a String as input and returns a String.
     * @return A new {@code UnaryOperator<String>} that caches the results of the original function.
     *         If the original function returns null for a given input, null will be cached and returned for subsequent calls with the same input.
     *
     * @see Function

        assertFalse(labelTypeHelper.matchLocale(Locale.US, Locale.UK));

        // Test with same language but different country
        Locale enUS = new Locale("en", "US");
        Locale enGB = new Locale("en", "GB");
        assertFalse(labelTypeHelper.matchLocale(enUS, enGB));

        // Test with same language, target has no country
        Locale en = new Locale("en");

   * possible with an unsafe cast which requires {@code keys} to actually be of type {@code K}.
   *
   * @since 11.0
   */
  /*
   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they
   * differ: <? extends Object> means "non-null types," while <?> means "all types."
   */
  @Override

 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},

 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},

 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},

   *     entriesInCommon(), entriesDiffering())
   * }
   */
  @Override
  int hashCode();

  /**
   * A difference between the mappings from two maps with the same key. The {@link #leftValue} and
   * {@link #rightValue} are not equal, and one but not both of them may be null.
   *
   * @since 2.0
   */
  @DoNotMock("Use Maps.difference")

 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},