Dev Essentials Week 4 Aug. 19 - Jackson Annotation - JsonProperty cannot be resolved to a type

In the new Week4 Augst 19 2015 new video Using JSON transformer w Jackson annotation, after added the com.mulesoft.traning to the src/main/java, in the walk through modifying the Flight.java class by adding the following JsonProperty. However, I got error saying "JsonProperty cannot be resolved to a type". What class reference did I miss?

public class Flight implements java.io.Serializable, Comparable<Flight> {

@JsonProperty("code")

String flightCode;

@JsonProperty("origin")

String origination;

@JsonProperty("emptySeats")

int availableSeats;

String departureDate;

String airlineName;

String destination;

double price;

String planeType;

public Flight() {

}