The problem was that I was using both the old and new jackson libraries
i.e. before I had
import org.codehaus.jackson.annotate.JsonProperty;
Which I had to change to below, to be consistent with the library I was using.
Since I was using maven that also meant updating my maven dependencies.
import com.fasterxml.jackson.annotation.JsonProperty;
For it to work, I needed the @JsonProperty annotation on the getter (putting it on the object didn’t work)
I found the answer here (thanks to francescoforesti)
@JsonProperty not working as expected