Spring Bean Naming Conventions

Direct Answer

Spring assigns a default name to a scanned component from its class name using JavaBeans-style decapitalization, so UserService becomes userService while an acronym name such as URLService may remain URLService. An @Bean method uses its method name by default. @Component/@Bean name attributes set names; @Qualifier adds candidate-selection metadata and does not generally rename the bean.

Code Example

// Default: bean name is "orderService"
@Service
public class OrderService { }

// Custom name: bean is now "orderSvc"
@Service("orderSvc")
public class OrderService { }

@Configuration
public class DatabaseConfig {
    // Bean name is "primaryDb" (method name)
    @Bean
    public DataSource primaryDb() {
        return new HikariDataSource();
    }

    // Custom name: bean is "reportsDatabase"
    @Bean(name = "reportsDatabase")
    public DataSource secondaryDb() {
        return new HikariDataSource();
    }
}

@Service
public class ReportService {
    private final DataSource dataSource;

    public ReportService(@Qualifier("reportsDatabase") DataSource ds) {
        this.dataSource = ds;  // Gets the secondaryDb bean
    }
}

Common Mistakes & Pitfalls

• Not knowing the lowercase convention: Freshers often look for a bean named "UserService" when Spring registered it as "userService"—the default name lowercases the first letter.
• Forgetting that @Bean uses method name: If your method is named customerRepo() but returns a CustomerRepository, the bean name is "customerRepo" not "customerRepository"—you must use that exact name in @Qualifier.
• Using custom names everywhere: Don't customize names unless you need to—if you only have one UserService bean, the default name works fine and changing it just adds confusion. Only customize when you have multiple beans of the same type or when the default name isn't clear enough.