In what cases should the specific Scope mechanism be used in the Spring Framework?

In the Spring Framework, the Scope mechanism defines the lifecycle and scope of a bean. The specific Scope to use depends on the requirements for the bean's lifetime and the context of its use:

• singleton (default): one instance for the entire Spring container. Used for services and components that should be shared.
• prototype: a new instance is created each time the bean is requested. Suitable for states that should not be shared.
• request (for web applications): the bean lives for a single HTTP request.
• session: the bean lives for the user's HTTP session.
• application: the bean lives for the entire lifecycle of the web application.

Example of using scope:

@Component
@Scope("prototype")
public class Task {
    // each call to getBean(Task.class) will create a new instance
}

The choice of scope depends on how long the bean should exist and in what context it is used.