How to resolve circular dependency in spring Framework

Category : Interview Questions | Sub Category : Spring Boot Interview Questions | By Prasad Bonam Last updated: 2023-08-14 16:32:50 Viewed : 47

Circular dependencies occur when two or more beans depend on each other directly or indirectly, forming a loop. Springs IoC container generally detects and prevents circular dependencies during bean creation, but sometimes it is possible to encounter such scenarios. Here are a few approaches to resolve circular dependencies in a Spring application:

1. Refactor Code: Consider redesigning your classes to reduce the circular dependencies. This might involve creating new classes to encapsulate certain behavior, breaking down larger classes, or rethinking the structure of your application to reduce the interdependency.

2. Constructor Injection: Use constructor injection instead of field or setter injection. Constructor injection can help avoid circular dependencies because all necessary dependencies are passed as parameters to the constructor at the time of object creation.

   javaCopy code
   public class A {
       private final B b;
   
       public A(B b) {
           this.b = b;
       }
   }
   
   public class B {
       private final A a;
   
       public B(A a) {
           this.a = a;
       }
   }
   

3. Setter Injection with @Autowired on Methods: If you need to use setter injection, you can annotate the setter methods with @Autowired and remove the @Autowired from the field. This can help avoid early initialization and break the circular dependency.

   javaCopy code
   public class A {
       private B b;
   
       @Autowired
       public void setB(B b) {
           this.b = b;
       }
   }
   
   public class B {
       private A a;
   
       @Autowired
       public void setA(A a) {
           this.a = a;
       }
   }
   

4. Using @Lazy: You can use the @Lazy annotation to lazily initialize beans. This can help break the circular dependency by deferring the initialization until the bean is actually requested.

   javaCopy code
   @Service
   @Lazy
   public class A {
       @Autowired
       private B b;
   }
   
   @Service
   @Lazy
   public class B {
       @Autowired
       private A a;
   }
   

5. Using Setter Methods: You can also use setter methods to manually set the dependencies after bean creation. This approach can allow you to control the order of dependency resolution.

Remember that while these approaches can help mitigate circular dependencies, it is still essential to carefully analyze your applications design and structure. Circular dependencies can indicate potential design issues, and sometimes, a reevaluation of your architecture might be necessary to achieve a cleaner and more maintainable solution.