Spring Circular Dependency Issue - V2.6 to Latest

Having an issue resolving circular dependency in a Spring Boot Starter project (version 3.1) with Gradle.

Using setter injection with @Autowired annotation.

After building the project, the following output displayed:

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2023-07-25T19:47:02.265-04:00 ERROR 27261 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

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

Description:

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

┌─────┐
|  classA
↑     ↓
|  classB
└─────┘


Action:

Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.

*Note: Project ran successfully with an older Spring Boot version (2.5.15). Also tested it using 2.6.0 - same issue occurred.

Appears to be an issue with versions 2.6 and above.

Application code below:

MainApp.java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MainApp {
    public static void main(String[] args) {
        SpringApplication.run(MainApp.class);
    }
}

ClassA.java

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class ClassA {
    private ClassB classB;

    @Autowired
    public void setClassB(ClassB classB) {
        this.classB = classB;
    }
}

ClassB.java

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class ClassB {
    private ClassA classA;

    @Autowired
    public void setClassA(ClassA classA) {
        this.classA = classA;
    }
}

*Please note: I have read the 2.6 release notes. Found that setting spring.main.allow-circular-references=true in application.properties file is not recommended. Also found that setter injection with @Autowired annotation hides the cycle. This should not occur due to being one of the resolution methods suggested in the Spring documentation.

Comment From: bclozel

Closing as a duplicate of https://github.com/spring-projects/spring-boot/issues/36286

Again, if you don't want to set that property you should avoid this pattern in the first place.

Comment From: zpreston123

@bclozel For use cases where setter injection is necessary, resolving this would help developers facing similar issues.

The following resolution methods worked in the code example above: 1. Constructor injection with @Lazy annotation 2. @PostConstruct annotation

As noted previously, setter injection worked using an older Spring Boot version (2.5.15).

Any assistance would be greatly appreciated.