NullPointerException in java execute

Question

I try to execute a gherkin method in my java main:

public class Prueba {

public static TestingScenario scenario;
@Inject
public Prueba(TestingScenario scenario) {

    this.scenario = scenario;
}

public static void main(String[] args) {
    scenario
            .http("")
            .post("")
            .body().json()
            .fromFile("")
            .send();
}

This is the error I get when executing main: