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

    private PathMappingDbm() {
    }

    public static PathMappingDbm getInstance() {
        return _instance;
    }

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

internal fun <T> readFieldOrNull(
  instance: Any,
  fieldType: Class<T>,
  fieldName: String,
): T? {
  var c: Class<*> = instance.javaClass
  while (c != Any::class.java) {
    try {
      val field = c.getDeclaredField(fieldName)
      field.isAccessible = true
      val value = field.get(instance)
      return if (!fieldType.isInstance(value)) null else fieldType.cast(value)

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

    private RequestHeaderDbm() {
    }

    public static RequestHeaderDbm getInstance() {
        return _instance;
    }

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

                  Class<Unsafe> k = Unsafe.class;
                  for (Field f : k.getDeclaredFields()) {
                    f.setAccessible(true);
                    Object x = f.get(null);
                    if (k.isInstance(x)) {
                      return k.cast(x);
                    }
                  }
                  throw new NoSuchFieldError("the Unsafe");
                });
      } catch (PrivilegedActionException e) {

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

    private LabelTypeDbm() {
    }

    public static LabelTypeDbm getInstance() {
        return _instance;
    }

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

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

    private FailureUrlDbm() {
    }

    public static FailureUrlDbm getInstance() {
        return _instance;
    }

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

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

    private RelatedContentDbm() {
    }

    public static RelatedContentDbm getInstance() {
        return _instance;
    }

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

  }

  @Override
  public <A extends Annotation> @Nullable A getAnnotation(Class<A> annotationType) {
    checkNotNull(annotationType);
    for (Annotation annotation : annotations) {
      if (annotationType.isInstance(annotation)) {
        return annotationType.cast(annotation);
      }
    }
    return null;
  }

  @Override
  public Annotation[] getAnnotations() {
    return getDeclaredAnnotations();
  }

   */
  @GwtIncompatible // Class.cast, Class.isInstance
  public static <X extends Throwable> void throwIfInstanceOf(
      Throwable throwable, Class<X> declaredType) throws X {
    checkNotNull(throwable);
    if (declaredType.isInstance(throwable)) {
      throw declaredType.cast(throwable);
    }
  }

  /**
   * Propagates {@code throwable} exactly as-is, if and only if it is an instance of {@code
   * declaredType}. Example usage:

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

    private WebAuthenticationDbm() {
    }

    public static WebAuthenticationDbm getInstance() {
        return _instance;
    }

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