What is the difference between @ComponentScans and @ComponentScan?

Question

I see that we have @org.springframework.context.annotation.ComponentScans and @org.springframework.context.annotation.ComponentScan.

1. How do we use @ComponentScans() ?
2. How is @ComponentScans() different from @ComponentScan({"com.org.abc", "com.org.xyz"})

Answer 1

Spring can automatically scan a package for beans if component scanning is enabled.

@ComponentScan configures which packages to scan for classes with annotation configuration. We can specify the base package names directly with one of the basePackages or value arguments (value is an alias for basePackages)

@Configuration
@ComponentScan(basePackages = "com.baeldung.annotations")
class VehicleFactoryConfig {}

Also, we can point to classes in the base packages with the basePackageClasses argument:

@Configuration
@ComponentScan(basePackageClasses = VehicleFactoryConfig.class)
class VehicleFactoryConfig {}

Both arguments are arrays so that we can provide multiple packages for each.

If no argument is specified, the scanning happens from the same package where the @ComponentScan annotated class is present.

@ComponentScan leverages the Java 8 repeating annotations feature, which means we can mark a class with it multiple times:

@Configuration
@ComponentScan(basePackages = "com.baeldung.annotations")
@ComponentScan(basePackageClasses = VehicleFactoryConfig.class)
class VehicleFactoryConfig {}

Alternatively, we can use @ComponentScans to specify multiple @ComponentScan configurations:

@Configuration
@ComponentScans({ 
    @ComponentScan(basePackages = "com.baeldung.annotations"), 
    @ComponentScan(basePackageClasses = VehicleFactoryConfig.class)
})
class VehicleFactoryConfig {}

You can found more Spring Bean Annotations

Answer 2

Take a look at documentation:

ComponentScans Container annotation that aggregates several ComponentScan annotations.

ComponentScan Configures component scanning directives for use with @Configuration classes.