!item.equals(NotAnInstance.EQUAL_TO_NOTHING));
      assertTrue(item + " must be Object#equals to itself", item.equals(item));
      assertEquals(
          "the Object#hashCode of " + item + " must be consistent",
          item.hashCode(),
          item.hashCode());
      if (!(item instanceof String)) {
        assertTrue(
            item + " must not be Object#equals to its Object#toString representation",

    <!-- Checks that the order of modifiers conforms to the suggestions in the
    Java Language specification, sections 8.1.1, 8.3.1 and 8.4.3. It is not that
    the standard is perfect, but having a consistent order makes the code more
    readable and no other order is compellingly better than the standard.
    The correct order is:
            public
            protected
            private
            abstract

            MessageDigest md5 = Crypto.getMD5();
            md5.digest(null);
        });
    }

    @Test
    @DisplayName("Should produce consistent hash results")
    void testHashConsistency() {
        // Given
        String input = "Test consistency";
        byte[] data = input.getBytes();

        // When
        MessageDigest md5_1 = Crypto.getMD5();
        MessageDigest md5_2 = Crypto.getMD5();

 *
 * <p>Each of the {@code standard} methods, where appropriate, uses the set's comparator (or the
 * natural ordering of the elements, if there is no comparator) to test element equality. As a
 * result, if the comparator is not consistent with equals, some of the standard implementations may
 * violate the {@code Set} contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be

 *
 * <p>Each of the {@code standard} methods, where appropriate, uses the set's comparator (or the
 * natural ordering of the elements, if there is no comparator) to test element equality. As a
 * result, if the comparator is not consistent with equals, some of the standard implementations may
 * violate the {@code Set} contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be

 * all cases, this implementation uses {@link Comparable#compareTo} or {@link Comparator#compare}
 * instead of {@link Object#equals} to determine equivalence of instances.
 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * Collection} contract, which is specified in terms of {@link Object#equals}.
 *

 * all cases, this implementation uses {@link Comparable#compareTo} or {@link Comparator#compare}
 * instead of {@link Object#equals} to determine equivalence of instances.
 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * Collection} contract, which is specified in terms of {@link Object#equals}.
 *

  /**
   * Returns an immutable map containing the same entries as {@code map}. If {@code map} somehow
   * contains entries with duplicate keys (for example, if it is a {@code SortedMap} whose
   * comparator is not <i>consistent with equals</i>), the results of this method are undefined.
   *
   * <p><b>Note:</b> Despite what the method name suggests, if {@code map} is an {@code
   * ImmutableClassToInstanceMap}, no copy will actually be performed.

        assertTrue(endLatch.await(10, TimeUnit.SECONDS), "All threads should complete");
        executor.shutdown();

        // Then - Session should be in consistent state
        // The double-check pattern should prevent inconsistent cleanup
        assertTrue(releaseCount.get() > 0 || acquireCount.get() > 0, "Release and acquire counts should be processed");
    }

    /**

   *
   * <p><b>Warning:</b> {@code keyPredicate} must be <i>consistent with equals</i>, as documented at
   * {@link Predicate#apply}. Do not provide a predicate such as {@code
   * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals.
   */
  public static <K extends @Nullable Object, V extends @Nullable Object> Map<K, V> filterKeys(