Cyclic dependency with constructor injection

[1zg12]

Background

Spring is discouraging use of filed injection, and in favor or constructor injection.

However, when the beans need to cross reference to each other. For example:

class BeanA{
    @Autowired
    public BeanA(BeanB beanB) {
        this.beanB= beanB;
    }
}

class BeanB{
    @Autowired
    public BeanB(BeanA beanA) {
        this.beanA= beanA;
    }

this will instead throw out exception

APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

┌─────┐
|  beanA defined in URL [jar:file:/...class]
↑     ↓
|  beanB defined in URL [jar:file:/....class]
↑     ↓
|  xx (field xx) 

Changes

Instead of just saying "Field injection is not recommended", can we make it clear, by adding

Field injection is not recommended **however, please don't constructor injection with circular reference** ?

?

Related Issues

• Cyclic dependency with setter injection and Java Config #25443
• Method invocation in same class when both methods are @Transactional, but method 2 never executes #27534
• Document how to optimize the dependency graph #30333

[sbrannen]

Related issues:

• Cyclic dependency with setter injection and Java Config #25443
• Method invocation in same class when both methods are @Transactional, but method 2 never executes #27534