Spring - #Autowired bean from #Configuration is null - spring

Question

I define a bean in a configuration class. I would like to autowire this bean in a component. However, the property stays null. E.g.:
Appconfiguration.java
#Configuration
public class AppConfiguration {
#Bean
public SomeType someObject() {
return new SomeType();
}
}
AppComponent.java
#Component
public class AppComponent {
#Autowired
private SomeType someObject; // TODO why null?
public AppComponent() { // note: passing a SomeType constructor argument works
System.out.println(someObject);
}
}
How can I autowire a bean defined in a configuration class?

Answer 1

Are you missing a fundamental detail that properties are injected after a bean is created? Have you tried access your property after a bean is fully initialized?
Update:
I've reworked your example a little to demonstrate you the difference:
#Test
public void initializationTest() {
try (AnnotationConfigApplicationContext context =
new AnnotationConfigApplicationContext()) {
context.register(AppConfiguration.class, AppComponent.class);
context.refresh();
}
}
#Configuration
public class AppConfiguration {
#Bean
public SomeType someObject() {
return new SomeType();
}
}
#Component
public class AppComponent {
#Autowired
private SomeType someObject;
public AppComponent() {
// Here properties are not yet injected by Spring IoC container
System.out.println(someObject); // Obviously prints null
}
/**
* Method is invoked after a bean is initialized and all its properties are being set.
*/
#PostConstruct
private void init() {
System.out.println(someObject); // Prints SomeType#6b419da
}
}
public class SomeType {
}
So basically bean lifecycle consists of the following steps:
1. Bean instance is created
2. Bean properties are set
3. In case bean implements Aware interfaces - those implemented methods are invoked
4. BeanPostProcessor#postProcessBeforeInitialization methods of custom bean post-processors are invoked
5. Initialization callbacks are invoked in the following order:
5.1. #PostConstruct method is invoked
5.2. InitializingBean#afterPropertiesSet() method is invoked
5.3. #Bean#initMethod() method is invoked
Bean is fully initialized now.
6. BeanPostProcessor#postProcessAfterInitialization methods of custom post-processors are invoked
are invoked.
7. Destruction callbacks are invoked in the following order:
7.1. #PreDestroy method is invoked
7.2. DisposableBean#destroy() method is invoked
7.3. #Bean#destroyMethod method is invoked