I see patchUser here:

https://github.com/FusionAuth/fusionauth-java-client/blob/1.19.0/src/main/java/io/fusionauth/client/FusionAuthClient.java#L1664

I think that's what you want.

You can, however, always full retrieval and a put as a workaround. That is recommended if you are changing an array, unless you want the behavior documented here: https://github.com/FusionAuth/fusionauth-issues/issues/441