Spring Boot basics
Spring Boot does not generate code and there is absolutely no requirement for XML configuration.
COMMON SPRING BOOT PROPERTIES « application.properties
Various properties can be specified inside your application.properties file, inside your application.yml file, or as command line switches.
# Preferred JSON mapper to use for HTTP message conversion to use Gson instead of Jackson.
spring.http.converters.preferred-json-mapper=gson
# JACKSON on/off features that affect the way Java objects are serialized.
spring.jackson.serialization.write-dates-as-timestamps=false