Does Jackson deserialise the second character to lowercase for a property

Question

We've defined a model in our service code as -

@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class SomeData {

    public boolean tnAvailable;

    @NonNull
    public String sTempChange;

    public boolean isTnAvailable() {
       return faAvailable;
    }

    public void setTnAvailable(boolean faAvailable) {
        this.faAvailable = faAvailable;
    }

    @Nonnull
    public String getSTempChange() {
        return sTempChange;
    }

    public void setSTempChange(@Nonnull String sTempChange) {
        this.sTempChange = sTempChange;
    }

}

When the api including the above model in response is queried , we get the response as -

"someData": {
    "tnAvailable": true,
    "stempChange": "trial_001"
}

What surprised us was the stempChange(notice lowercase t) instead of sTempChange in the attributes of the response.

Suspecting the cause to be Jackson com.fasterxml.jackson.core:jackson-core:2.5.2 while serializing and deserializing of the objects during API calls since we do not alter the attribute using any other getter-setter ot wrapper. Why would this so happen and is serialization/deserialization the correct direction to look for this?

Edit - From the comment by @Windle, trying to explain what's different here. I re-iterate "The question though there relates pretty much to the same situation. Yet I 'm looking forward to the reason's for such implementation and documentation in fasterxml as well."

Answer 1

Handling of multiple leading capital letters in getters/setters (like "getURL()", or "getFName()"). By default, Jackson will simply lower-case ALL leading upper-case letters, giving "url" and "fname". But if you enable MapperFeature.USE_STD_BEAN_NAMING (added in Jackson 2.5), it will follow what Java Bean naming convention would do, which is only lower-case a single upper-case leading letter; if multiple found, do nothing. That would result in properties "URL" and "FName".