Agfdhyk

The following produces a null error ("A" is null), but I am not sure why. Is the bean instantiated before the property value is set?

package org.ets.readtogether.queuing;



import org.springframework.beans.factory.annotation.Value;

import org.springframework.stereotype.Component;



@Component("Abean")

public class Test {



    @Value("${send.timeout.secs}")

    public Integer A;



    public int B = A * 1000;

}

Spring adds all the dependencies injected in an object after instantiating it. Object instantiation precedes any @Autowired dependency injection or @Value value assignment done by Spring.

The instantiation of your class's object fails even before Spring has the object to inject dependencies because the statement public int B = A * 1000; is called during object instantiation.

In order to assign the variable B a value after Spring has finished all injections, perform the operation in either a @PostConstruct method or in an @AutoWired constructor.

   public int B; // remove the assignment here.



   @PostConstruct

   public void postConstruct () {

       this.B = A * 1000;

   }

The above method would be called after the object has been instantiated and after Spring has done its work.

Try this:

@Component("Abean")

public class Test {



    @Value("${send.timeout.secs}")

    public Integer A;



    public int B;



    @PostConstruct

    public void init() {

       B = A * 1000;

    }

}

Good example here