[HELP] Using Spring Boot and CrudRepository, how to send Null/None in specific field?

I’m creating a project in which I need to insert four rows into a postgresql table, where I have two string fields and two date fields. The first string/date pair will be defined at row insertion, and the second pair will be updated sometime later with actual values. As of now I’m trying to do this using .save() in CrudRepository. When I do this in python with SQLAlchemy, I can just select the columns I want to insert, and the other columns are left with a <null> value by postgres. How do I replicate this in Spring Boot with CrudRepository? As of know I have to set some dummy value for the last pair as it insists on having to fill each column.