//                                                                           =========
    private static final ElevateWordDbm _instance = new ElevateWordDbm();

    private ElevateWordDbm() {
    }

    public static ElevateWordDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final ClickLogDbm _instance = new ClickLogDbm();

    private ClickLogDbm() {
    }

    public static ClickLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

  // TODO(user): cache all field accesses in local vars

  /** Creates an empty {@code CompactHashSet} instance. */
  public static <E extends @Nullable Object> CompactHashSet<E> create() {
    return new CompactHashSet<>();
  }

  /**
   * Creates a <i>mutable</i> {@code CompactHashSet} instance containing the elements of the given
   * collection in unspecified order.
   *

    //                                                                           =========
    private static final JobLogDbm _instance = new JobLogDbm();

    private JobLogDbm() {
    }

    public static JobLogDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final KeyMatchDbm _instance = new KeyMatchDbm();

    private KeyMatchDbm() {
    }

    public static KeyMatchDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

                concatValues(existingValues, readings[i]);
                map.put(FieldNames.READING_PREFIX + i, existingValues.stream().distinct().toList());
            } else {
                final String[] values = readings[i] == null ? null : Arrays.stream(readings[i]).distinct().toArray(n -> new String[n]);
                map.put(FieldNames.READING_PREFIX + i, values);
            }
        }

    //                                                                           =========
    private static final BadWordDbm _instance = new BadWordDbm();

    private BadWordDbm() {
    }

    public static BadWordDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final BoostDocumentRuleDbm _instance = new BoostDocumentRuleDbm();

    private BoostDocumentRuleDbm() {
    }

    public static BoostDocumentRuleDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

      if (Serializable.class.isAssignableFrom(classToTest)) {
        try {
          Object instance = tester.instantiate(classToTest);
          if (instance != null) {
            if (isEqualsDefined(classToTest)) {
              SerializableTester.reserializeAndAssert(instance);
            } else {
              SerializableTester.reserialize(instance);
            }
          }
        } catch (Throwable e) {

    //                                                                           =========
    private static final FileAuthenticationDbm _instance = new FileAuthenticationDbm();

    private FileAuthenticationDbm() {
    }

    public static FileAuthenticationDbm getInstance() {
        return _instance;
    }

    // ===================================================================================