org.springframework.scheduling.annotation

## Annotation Type Async

    @Target(value={METHOD,TYPE})
    @Retention(value=RUNTIME)
    @Documented
    public @interface Async

Annotation that marks a method as a candidate for asynchronous execution. Can also be used at the type level, in which case all of the type's methods are considered as asynchronous.

In terms of target method signatures, any parameter types are supported. However, the return type is constrained to either `void` or `Future`. In the latter case, the `Future` handle returned from the proxy will be an actual asynchronous `Future` that can be used to track the result of the asynchronous method execution. However, since the target method needs to implement the same signature, it will have to return a temporary `Future` handle that just passes the return value through: e.g. Spring's `AsyncResult` or EJB 3.1's `AsyncResult`.

Since:
  3.0
Author:
  Juergen Hoeller, Chris Beams
See Also:
  `AnnotationAsyncExecutionInterceptor`, `AsyncAnnotationAdvisor`

### Optional Element Summary

Optional Elements
`String` `value` A qualifier value for the specified asynchronous operation(s).

### Element Detail

#### value

    public abstract String value

A qualifier value for the specified asynchronous operation(s).

May be used to determine the target executor to be used when executing this method, matching the qualifier value (or the bean name) of a specific `Executor` or `TaskExecutor` bean definition.

When specified on a class level `@Async` annotation, indicates that the given executor should be used for all methods within the class. Method level use of `value()` always overrides any value set at the class level.

Since:
  3.1.2

Default:
  ""