AnnotationConfigApplicationContext has not been refreshed yet - what's wrong?

My very basic spring application stopped working and I can't understand what's happened. pom.xml:

<properties>
    <spring.version>4.1.1.RELEASE</spring.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>
</dependencies>

Config class:

@Configuration
public class MyConfig {

@Bean
public HelloWorld helloWorld() {
         return new HelloWorld();
    }
}

Bean class:

public class HelloWorld {
    private String message;

    public void setMessage(String message) {
        this.message = message;
    }
    public String getMessage() {
         return message;
    }
}

Entry point of application:

public class MainApp {
public static void main(String[] args) {
    AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
    ctx.register(MyConfig.class);
    HelloWorld bean = ctx.getBean(HelloWorld.class);
    bean.setMessage("ladjfaj");
    System.out.println(bean.getMessage());
}
}

And I'm getting an error

Exception in thread "main" java.lang.IllegalStateException: org.springframework.context.annotation.AnnotationConfigApplicationContext@6ebf8cf5 has not been refreshed yet at org.springframework.context.support.AbstractApplicationContext.assertBeanFactoryActive(AbstractApplicationContext.java:943) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:967) at com.nikolas.config.MainApp.main(MainApp.java:12)

You have to call ctx.refresh() before you can call ctx.getBean(HelloWorld.class);