code: private void doCreateHelperForProp(final PropertyDescriptor propertyDescriptor,
        final BeanHelper parent, final TreeLogger logger, final GeneratorContext context)
        throws UnableToCompleteException {
      final Class<?> elementClass = propertyDescriptor.getElementClass();
      if (GwtSpecificValidatorCreator.isIterableOrMap(elementClass)) {
        if (parent.hasField(propertyDescriptor)) {
          final JClassType type = parent.getAssociationType(propertyDescriptor, true);
  
          this.createHelper(type.getErasedType(), logger, context);
        }
        if (parent.hasGetter(propertyDescriptor)) {
          final JClassType type = parent.getAssociationType(propertyDescriptor, false);
  
          this.createHelper(type.getErasedType(), logger, context);
        }
      } else {
        if (serverSideValidator.getConstraintsForClass(elementClass).isBeanConstrained()) {
          this.createHelper(elementClass, logger, context);
        }
      }
    }
docs: Creates the appropriate BeanHelper for a property on a bean.