If you are new to spring boot please refer to official spring boot documentation.
As spring boot was used to create this application most of the things are set up out of the box. Only thing left to set up is the APILayer api key. It should be set in the freefi.exchange.integration.api-key property. It is confidential, therefore, please do not commit the application.properties file with the set value. You can configure it in many ways, as described in spring boot documentation.
If you need to check if 131052-308T is a proper finnish (FI) ssn then you need to execute such request:
curl -X POST -H 'Content-Type: application/json' -i 'http://localhost:8080/validate_ssn?country_code=FI' --data '{"ssn": "131052-308T"}'
If you would like to check how much EUR you can get for 2 USD then you should run such request:
curl -X GET -i 'http://localhost:8080/exchange_amount?from=USD&to=EUR&from_amount=2'
In case you would like to get a docker image of this application please use default spring mechanism - just invoke mvn spring-boot:build-image as described in documentation.