How spring.datasource.validationQuery: "select 1" being running without being specified?

“SELECT 1” query running on certain intervals against on Postgres database but I did not specify the validation query at all.

I am not sure why a validationQuery would be running without configuration and Why is the validationQuery element needed in the spring datasource?

Spring Datasource Configuration USED:

    databaseSchemaUpdate: false
    driver-class-name: ${spring_datasource_driver_class_name}
      maximum-pool-size: 50
      max-lifetime: 300000
      idle-timeout: 120000
      minimum-idle: 20
      transaction-isolation: TRANSACTION_READ_COMMITTED
    url: ${spring_datasource_url}
    username: dbuser
    password: pwd

Additional App Details

Spring-Boot: (v2.1.2.RELEASE)
Camunda BPM: (v7.12.0)
Camunda BPM Spring Boot Starter: (v3.4.1)