CODEWITHSUNDEEP
springannotations
Marco
Marco

Reputation: 15909

When annotating a class with @Component, does this mean it is a Spring Bean and Singleton?

Being fairly new to Spring I have a question about annotating a class. When annotating a class with @Component does this mean this class will be a Spring Bean and by default a singleton?

Upvotes: 157

Views: 128615

Answers (2)

Bozho
Bozho

Reputation: 597046

Yes, that is correct, @Component is a Spring bean and a Singleton.

If the class belongs to the service layer you may want to annotate it with @Service instead

But have in mind that in order for these annotations to be detected, you need to place this line in applicationContext.xml:

<context:component-scan base-package="com.yourcompany" />

About singletons - spring beans are all in singleton scope by default. The only thing you have to have in mind is that you should not store state in field variables (they should only hold dependencies). Thus your application will be thread-safe, and you won't require a new instance of a bean each time. In other words, your beans are stateless.

Upvotes: 189

Lea Zus
Lea Zus

Reputation: 569

By default - Yes.

However, you can override this behavior using the @Scope annotation. For example: @Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)

Upvotes: 46

Related Questions