Not understanding this error message. "Bummer: There is something wrong with your package declaration."

public class Contact{

  private int id;
  private String firstName;
  private String lastName;
  private String email;




  public int getId(){
    return id;
  }

  public void setId(int id){
    this.id = id;
  }



  public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String name) {
        this.firstName = name;
    }

  public String getLastName() {
        return lastName;
    }

    public void setLastName(String name) {
        this.lastName = name;
    }


  public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}