@Required causes exceptions even when bean is initialized

I would like for Spring Boot to throw an exception if any of my beans are not fully configured during initialization. I thought that the correct way to do that would be to annotate the relevance bean methods with @Required, but it does not behave as I expect.

application.yml:

my_field: 100

Simple bean class:

package com.example.demo;

import org.springframework.beans.factory.annotation.Required;
import org.springframework.stereotype.Component;

@Component
public class MyProperties {
    private int myField;

    public MyProperties(){}

    @Required
    public void setMyField(int myField) {
        this.myField = myField;
    }

    @Override
    public String toString() {
        return  "{myField=" + myField + '}';
    }
}

My application class:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;

import javax.annotation.PostConstruct;

@SpringBootApplication
public class DemoApplication {

    @Bean
    @ConfigurationProperties
    public MyProperties getMyProperties() {
        return new MyProperties();
    }

    @PostConstruct
    public void init() {
        MyProperties myProperties = getMyProperties();
        System.out.println(myProperties);
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

In the init method of DemoApplication I am printing the resulting bean object. Without the @Required annotation it is loaded correctly and prints {myField=100}. However, when I add the annotation it throws this exception:

org.springframework.beans.factory.BeanInitializationException: Property 'myField' is required for bean 'myProperties'

This is despite the fact that the config file contains the required value.

What is the correct to tell Spring that a field is required?

Solution

From the docs

Spring Boot will attempt to validate @ConfigurationProperties classes whenever they are annotated with Spring’s @Validated annotation. You can use JSR-303 javax.validation constraint annotations directly on your configuration class. Simply ensure that a compliant JSR-303 implementation is on your classpath, then add constraint annotations to your fields

You should declare myField as follows:

@NonNull
private int myField;