How to resolve the problem of cyclic dependencies when using dependency injection?

Cyclic dependencies in dependency injection occur when two or more components depend on each other directly, leading to infinite recursion during object creation.

Ways to resolve:

1. Refactoring architecture — reconsider the design to eliminate dependency cycles, for example, by extracting a common interface or service used by both sides.

2. Using lazy initialization (Lazy Injection) — inject dependencies via proxies or supply them not in the constructor, but through setters or methods, so objects are created without immediately resolving all dependencies.

3. Injection via interfaces and factories — instead of directly injecting an object, inject a factory that creates the required object on demand, thereby breaking the cycle.

4. Using @Lazy in Spring:

@Component
public class A {
    private final B b;

    public A(@Lazy B b) {
        this.b = b;
    }
}

@Component
public class B {
    private final A a;

    public B(A a) {
        this.a = a;
    }
}

Here, @Lazy causes Spring to delay the creation of the dependency, which helps avoid the cycle.

5. Using providers (Provider<T>) — inject not the object itself, but a provider that creates the object upon request.

Ultimately, the best approach is to avoid cyclic dependencies at the architecture level, and if that's not possible, use lazy initialization or factories.