An aggregator configured using annotations can look like this.

public class Waiter {
  ... 

  @Aggregator  
  public Delivery aggregatingMethod(List<OrderItem> items) {
    ...
  }

  @CompletionStrategy 
  public boolean completionChecker(List<Message<?>> messages) {
    ...
  }

}

All the configuration options provided by xml element are available for the @Aggregator annotation.

The aggregator can be either referenced explicitly from XML or, if the @MessageEndpoint is defined on the class, detected automatically through classpath scanning.