[FIXED] What is given priority in below scenario @Bean or @Component?

Issue

I am learning concepts of Spring & I came across @Bean & @Component annotations. I want to know what will happen in below scenario:

@Configuration
class ConfigClass {

  @Bean
  public ComponentClass ComponentClass() {
    return new ComponentClass(someDependency1, someDependency2, someDependency3);
  }
}

@Component
class ComponentClass{
  private SomeDependency1 sd1;
  private SomeDependency2 sd2;
  private SomeDependency3 sd3;

  public ComponentClass(SomeDependency1 sd1, SomeDependency2 sd2, SomeDependency3 sd3) {
    /* initialize here */
  }
}

I have declared ComponentClass as @Component which means it is a spring bean now. But I have also defined a @Bean for it in config class separately.

1. Which of these beans will be actually used as by default Spring is singleton?

2. What happens when I remove @Component?

Solution

Spring will notice a mistake and throw NoUniqueBeanDefinitionException during application startup. If you remove @Component annotation it will work as expected, @Bean will be used for initialization.

Answered By - Maksym Rudenko
Answer Checked By - Pedro (JavaFixing Volunteer)