Spring Boot - #Configuration class is null in spring component - spring

Question

I have a problem with spring boot when using autowired on a configuration class.
I have minimized the problem by creating a small spring boot project on github.
I created the MyBean class declaring it as #Component and attempting the autowired of the MyConf class which is declared as #Configuration (and reads the property in the file myconfig.properties). In theory, everything is in the spring context, but when the application starts myConfigProp variable in MyBean is null.
Where am I wrong?
I also tried the following solutions, all not working:
Insert the #DependsOn in MyBean
Commented on the #Component and configured MyBean as #Bean of spring
The last test I did (not present on github project) was to pass MyConfigProp as a parameter in MyBean constructor, and it worked.
#Component
public class MyBean {
String message;
public MyBean(MyConfigProp myConfigProp) {
this.message = myConfigProp.getMessage();
}
}
I am somewhat confused.

Answer 1

Looks like you're not Autowiring MyConfigProp's into MyBean:
#Component
public class MyBean {
String message;
#Autowired
public MyBean(MyConfigProp myConfigProp) {
this.message = myConfigProp.getMessage();
}
}

Answer 2

You need to add the #EnableConfigurationProperties(MyConfigProp.class) in your MyBean class so that it looks like:
MyBean.java
#Component
#EnableConfigurationProperties(MyConfigProp.class)
public class MyBean {
String message;
#Autowired
public MyBean(MyConfigProp myConfigProp) {
this.message = myConfigProp.getMessage();
}
}
MyConfigProp.java
#PropertySource("classpath:myconfig.properties")
#ConfigurationProperties(prefix = "config")
public class MyConfigProp {
private String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}

Answer 3

I tried all the solutions and the only one that actually solve the problem is to pass MyConfigProp as a parameter in MyBean constructor, as from post, even without #Autowired.
Code update
#Component
public class MyBean {
String message;
public MyBean (MyConfigProp myConfigProp) {
this.message = myConfigProp.getMessage ();
}
}
I share the rest for knowledge.
In detail, trying the proposed solutions, the result was:
Adding the #Component stereo-type on MyConfigProp annotation to
use #Autowired in MyBean not work, even adding #ComponentScan. It still launches NullPointerException
The annotation #EnableConfigurationProperties seems to be useful only if
#Configuration is not used on MyConfigProp and does not solve the problem
From the tests and the documentation readings, if I understand correctly, the problem is that I try to use the object in # Autowired in theMyBean constructor and, during the creation of this, Spring has not yet instantiatedMyConfigProp, hence theNullPointerException.
I updated the code by adding a solutions package with the possible solutions:
MyBeanWorked: Solution shown above.
WithoutConstructor: By moving the instruction into a method, the
startup is successful and the application works.
WorkedWithInjectProp: Not declared as #Component but configured as
#Bean. A little longer but, needing only a property, perhaps cleaner.
More details in the code.
I hope I have done something pleasant.