Hi Matt, Great to hear that you're progressing with your implementation! the spec? Yes, you're on the right path ;) There are two separate aspects here: a) invocation of value extractors in order to obtain a container's elements and b) rules for constructing property paths. On a), value extractors are called to cascade into containers when processing @Valid (where 2.0 generalizes the 1.1 notion of cascaded validation, see [1]) and when processing container element constraints (e.g. List<@Positive Integer>). On b), the rules are described in [2]. Specifically: "If a parameter ... of a ... constructor is traversed: * a ... ConstructorNode object is added to the Path * ... a ParameterNode object is added to the Path * if the parameter ... is a List or an array, the following Node object added contains the index value in getIndex(). And: "For a container element constraint: * if the corresponding value extractor has specified a node name when calling one of the receiver methods, a ContainerElementNode object with that name is added to the Path" I.e. you'll see path nodes with the name returned by a value extractor in the second case, but not the first. One more case where you will see a node with that name, is nested cascaded validation (Map<String, List<@Valid Address>>). And finally, no node will be appended if the extractor doesn't provide a node name. This is to suppress addition of a node for wrapper-style containers such as Optional<@Positive Integer> or @Positive OptionalInt. Hth, --Gunnar [1] http://beanvalidation.org/2.0/spec/#constraintdeclarationvalidationproces... [2] http://beanvalidation.org/2.0/spec/#validationapi-constraintviolation 2018-03-03 0:27 GMT+01:00 Matt Benson <mbenson(a)apache.org&gt;: