Java Spring Boot: Circular Dependency guide with Constructor Injection in Version 2.5.4
I'm a bit lost with This might be a silly question, but I'm stuck on something that should probably be simple. I'm working with a circular dependency scenario in my Spring Boot application version 2.5.4 when trying to use constructor injection. I have two services, `UserService` and `EmailService`, where `UserService` depends on `EmailService`, and `EmailService` also has a method that requires `UserService`. This leads to the following behavior: ``` behavior creating bean with name 'userService': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: ... `UserService` has a circular reference with `EmailService`. ``` Here’s a snippet of my code: ```java @Service public class UserService { private final EmailService emailService; @Autowired public UserService(EmailService emailService) { this.emailService = emailService; } // Other methods } @Service public class EmailService { private final UserService userService; @Autowired public EmailService(UserService userService) { this.userService = userService; } // Other methods } ``` I've tried using `@Lazy` annotation on one of the services, like this: ```java @Lazy @Autowired public EmailService(UserService userService) { this.userService = userService; } ``` However, it leads to a different behavior: `Circular reference involving the 'userService' bean`. I've also considered refactoring the code to use setter injection, but I would prefer to stick with constructor injection for clarity and immutability. Is there a better way to resolve this circular dependency while keeping constructor injection in place? Am I missing something obvious? For context: I'm using Java on macOS. I've been using Java for about a year now. For reference, this is a production desktop app.