# Constructor cycle vs field cycle: plain Spring and Spring Boot


--- plain Spring, constructor cycle (CtorA <-> CtorB) ---
started: false
root cause: org.springframework.beans.factory.BeanCurrentlyInCreationException
Error creating bean with name 'ctorA': Requested bean is currently in creation: Is there an unresolvable circular reference or an asynchronous initialization dependency?

--- plain Spring, field cycle (FieldA <-> FieldB) ---
started: true
FieldA.b is FieldB: true

--- Spring Boot, field cycle, default settings ---
FAILED: BeanCurrentlyInCreationException: Error creating bean with name 'fieldA': Requested bean is currently in creation: Is there an unresolvable circular reference or an asynchronous initialization dependency?

--- Spring Boot, field cycle, spring.main.allow-circular-references=true ---
started

--- Spring Boot, constructor cycle, spring.main.allow-circular-references=true ---
FAILED: BeanCurrentlyInCreationException: Error creating bean with name 'ctorA': Requested bean is currently in creation: Is there an unresolvable circular reference or an asynchronous initialization dependency?