You are free to use any of the standard Spring Framework techniques to define your beans and their injected dependencies. For simplicity, we often find that using @ComponentScan to find your beans, in combination with @Autowired constructor injection works well.

If you structure your code as suggested above (locating your application class in a root package), you can add @ComponentScan without any arguments. All of your application components (@Component, @Service, @Repository, @Controller etc.) will be automatically registered as Spring Beans.

Here is an example @Service Bean that uses constructor injection to obtain a required RiskAssessor bean.

package com.example.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class DatabaseAccountService implements AccountService {

    private final RiskAssessor riskAssessor;

    @Autowired
    public DatabaseAccountService(RiskAssessor riskAssessor) {
        this.riskAssessor = riskAssessor;
    }

    // ...

}

And if a bean has one constructor, you can omit the @Autowired.

@Service
public class DatabaseAccountService implements AccountService {

    private final RiskAssessor riskAssessor;

    public DatabaseAccountService(RiskAssessor riskAssessor) {
        this.riskAssessor = riskAssessor;
    }

    // ...

}

	Tip
	Notice how using constructor injection allows the riskAssessor field to be marked as final, indicating that it cannot be subsequently changed.