Creating object inside class method

Imagine you're developing an REST API.

You need a method that provides something basic information for the setup of the service, do you think it's a good practice to initialize the service class outside of the constructor? What other options might be better?

public class Controller {

    private Service service;

    @PostMapping(value="/setup")
    public void setup(@RequestBody SetupInfo setupInfo) {
        service = new ServiceImpl(setupInfo);
    }

    @PutMapping(value="/anotherMethod")
    public void anotherMethod(@RequestBody Something something) {
        marsRover.something(something);
    }
}