XStream Serialization: SortedSet vs. NavigableSet vs. TreeSet

[Ullrich Hafner]

In one of my serialized instances I am using a TreeSet to store some properties.

When I declare the Java field as SortedSet (interface) or TreeSet (class), the Jenkins XStream correctly serializes the model. However, when I declare my field as NavigableSet (interface), then the serialization resolves the field to null.

Shouldn’t XStream always pick the correct dynamic type (and not the static type) when serializing things? Or did we specify a specific converter that uses a static type?

[Jesse Glick]

On Mon, Oct 17, 2022 at 5:43 AM Ullrich Hafner <ullrich...@gmail.com> wrote:

Shouldn’t XStream always pick the correct dynamic type (and not the static type) when serializing things?

As far as I know it does, but then again the representation for exotic collection types is complex.

You should declare the persisted field to be of some simpler type, preferably `ArrayList`. If you need to enforce uniqueness, sorting, etc. in memory during operations, do so using any other mechanism, perhaps a `transient` field.