TO DO: "Sort empty types?"

Hello Oracle,

When reading the nosql-java-sdk, I noticed there is a TO DO in the src/main/java/oracle/nosql/driver/values/NullValue.java file and I would like to work on it.

To my understanding, the NullValue class inherits from FieldValue. In the code below, the compareTo method is used to compare two FieldValue objects, returning a value indicating whether the current object (this) is less than, equal to, or greater than the other object. If the other object is a NullValue object, then return 0 else -1.

    @Override
    public int compareTo(FieldValue other) {
        if (other instanceof NullValue) {
            return 0;
        }
        /* TODO: sort empty types? */
        return -1;
    }

Although I did not understand the reason to 'sort empty types' comment, I would like to open this issue to suggest a solution.
The final solution should improve the base code to satisty edge cases.

Start with src/main/java/oracle/nosql/driver/values/NullValue.java and the compareTo entry point, then inspect the FieldValue comparison contract. The issue does not define how empty types should be ordered, so first establish the intended ordering and edge cases. Done means the behavior is agreed, implemented, and covered by relevant tests.