Spring Boot Actuator - env endpoint provides response with active_profiles and property_sources

Question

Once I invoke spring actuator endpoint (http://localhost:8080/actuator/env) it provides response in following format which include _ in between,

{
active_profiles: [ ],
property_sources: [
 .....

This includes underscore in between, and this is different comparing to our other services. My expected response is without '_' as follows:

activeProfiles: [ ],
propertySources: [

I am not sure why it generates response with '_' can someone please help on this, Thanks