```
@Retention(RUNTIME)
@Target(TYPE)
@Documented
public @interface Asynchronous
```
An annotation to specify that command execution should be done asynchronously.
How exactly this is implemented is up to the command handler that evaluates this command. Usually the command will be execute in some thread pool. But it would also be valid for a command handler to execute each asynchronous command execution in a new thread, so using this can add significant overhead if overused. As long as a command is not doing long-running or blocking operations it might be a good idea to not execute the command asynchronously. But if long-running or blocking operations are done in the command code directly, depending on the underlying message framework it might be a good idea to execute the command asynchronously to not block message dispatching which could introduce serious lag to the command execution.
As the command executions are potentially done on different threads, special care must be taken if the command holds state, to make sure this state is accessed in a thread-safe manner. This can of course also happen without the command being configured asynchronously if the underlying message framework dispatches message events on different threads.
Alternatively to using this annotation the Command.isAsynchronous() method can be overwritten. If that method is overwritten and this annotation is used, the method overwrite takes precedence. That method is also what should be used to retrieve the configured state.

See Also:

Command.isAsynchronous()

Annotation Type Asynchronous