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Package jakarta.enterprise.context

Annotations and interfaces relating to scopes and contexts.

See: Description

Package jakarta.enterprise.context Description

Annotations and interfaces relating to scopes and contexts.

A scope type is a Java annotation annotated @Scope or @NormalScope. The scope of a bean determines the lifecycle and visibility of its instances. In particular, the scope determines:

Built-in scopes

The following built-in scopes are provided: @Dependent, @RequestScoped, @ConversationScoped, @SessionScoped, @ApplicationScoped, @Singleton.

The container provides an implementation of the Context interface for each of the built-in scopes. The built-in request, session, and application contexts support servlet, web service and EJB invocations. The built-in conversation context supports JSF requests.

For other kinds of invocations, a portable extension may define a custom context object for any or all of the built-in scopes. For example, a third-party web application framework might provide a conversation context object for the built-in conversation scope.

The context associated with a built-in scope propagates across local, synchronous Java method calls, including invocation of EJB local business methods. The context does not propagate across remote method invocations or to asynchronous processes such as JMS message listeners or EJB timer service timeouts.

Normal scopes and pseudo-scopes

Most scopes are normal scopes. Normal scopes are declared using @NormalScope. If a bean has a normal scope, every client executing in a certain thread sees the same contextual instance of the bean. This instance is called the current instance of the bean. The operation Context.get(Contextual) of the context object for a normal scope type always returns the current instance of the given bean.

Any scope that is not a normal scope is called a pseudo-scope. Pseudo-scopes are declared using @Scope. The concept of a current instance is not well-defined in the case of a pseudo-scope. Different clients executing in the same thread may see different instances of the bean. In the extreme case of the @Dependent pseudo-scope, every client has its own private instance of the bean.

All built-in scopes are normal scopes, except for the @Dependent and @Singleton pseudo-scopes.

Contextual and injected reference validity

A reference to a bean obtained from the container via programmatic lookup is called a contextual reference. A contextual reference for a bean with a normal scope refers to the current instance of the bean. A contextual reference for a bean are valid only for a certain period of time. The application should not invoke a method of an invalid reference.

The validity of a contextual reference for a bean depends upon whether the scope of the bean is a normal scope or a pseudo-scope:

A reference to a bean obtained from the container via dependency injection is a special kind of contextual reference, called an injected reference. Additional restrictions apply to the validity of an injected reference:

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