code: @Override
      public ValidationResult validate(@Nullable final Object value) {
          if (value instanceof ObjectId) {
              return new ValidationResult.ValidationPassed();
          } else {
              return new ValidationResult.ValidationFailed(String.valueOf(value) + " is not a valid ObjectId!");
          }
      }
docs: Validates: Object is not {@code null} and of type {@link ObjectId}.
  
  @param value The object to check
  @return validation result