Avoid Using `@Qualifier` on `@Bean` Methods

Why this matters

Using `@Qualifier` on `@Bean` methods is redundant and can cause unnecessary complexity in Spring applications. Beans should be titled explicitly using the method title or the `title` attribute.

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

@Configuration
public class MyConfiguration {
  @Bean
  @Qualifier("myService")
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Prefer

@Configuration
public class MyConfiguration {
  @Bean
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean(title="betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

More snippets

Bad

@Configuration
public class MyConfiguration {
  @Bean
  @Qualifier("myService")
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Good

@Configuration
public class MyConfiguration {
  @Bean
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean(title="betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Related rules

From the same buckets as this rule.

Critical

Avoid Returning Null in Non-Async Task Methods

Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.

error-handlingreadability-refactor+1

Critical

Prefer `str.replace()` Over `re.sub()` for Simple Cases

Detect uses of `re.sub()` where regular expressions are not needed. For simple string replacements, `str.replace()` is more efficient and should be used instead.

performance-efficiencystack-python+1

Critical

Use Factory Method Injection in `@Configuration` Classes

Ensure that factory method injection is used in `@Configuration` classes instead of `@Autowired` field injection.

module-architecturestyle-conventions

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

@Configuration
public class MyConfiguration {
  @Bean
  @Qualifier("myService")
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Prefer

@Configuration
public class MyConfiguration {
  @Bean
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean(title="betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

More snippets

Bad

@Configuration
public class MyConfiguration {
  @Bean
  @Qualifier("myService")
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean
  @Qualifier("differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Good

@Configuration
public class MyConfiguration {
  @Bean
  public MyService myService() {
    // ...
    return new MyService();
  }

  @Bean(title="betterService")
  public MyService aBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="evenBetterService")
  public MyService anEvenBetterService() {
    // ...
    return new MyService();
  }

  @Bean(title="differentService")
  public MyBean aDifferentService() {
    // ...
    return new MyBean();
  }
}

Related rules

From the same buckets as this rule.

Critical

Avoid Returning Null in Non-Async Task Methods

Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.

error-handlingreadability-refactor+1

Critical

Prefer `str.replace()` Over `re.sub()` for Simple Cases

Detect uses of `re.sub()` where regular expressions are not needed. For simple string replacements, `str.replace()` is more efficient and should be used instead.

performance-efficiencystack-python+1

Critical

Use Factory Method Injection in `@Configuration` Classes

Ensure that factory method injection is used in `@Configuration` classes instead of `@Autowired` field injection.

module-architecturestyle-conventions