Invoke another bean's method in @PostConstruct raised a null pointer ex

Question

I am using Spring4.

There are three beans: bean1 and bean2 and bean3 ,and in my bean1's @PostConstruct method,i invoke bean2's method,this method of bean2 will invoke bean3's method,and i got a NPE, beacuse method in bean2 is invoked, bean3 hasn't been injected yet.

How to avoid this kind of situation? The code looks something like this:

@Service
public class Bean1 {
    @Autowired
    private Bean2 bean2;
    @PostConstruct
    public void init() {
        // invoke bean2's method
        bean2.test();
    }

}

@Service
public class Bean2 {
    @Autowired
    private Bean3 bean3;

    public void test() {
        // invoke bean3's method,got a null pointer ex,because bean3 is null.
        bean3.xxx();
    }
}

Answer 1

What Ever code posted by you, I don't thing you may get any problem. Just Check in your whole code you are creating bean yourself not by spring its only one case.

If you are creating bean yourself then spring wont be inject anything and provide bean object as null. post

Answer 2

You need the @DependsOn annotation to make sure bean initialization happens in the order you expect.