カレンダーオブジェクトはデータベース内で更新されませんが、セッション内で更新されます

Question

CalendarのstartTimeとendTimeを持つエンティティBeanの予定を表しています。これは、JPAを使用してTIMESTAMPとして格納されます。 Appointmentオブジェクトの開始時刻と終了時刻を編集すると、セッション中にオブジェクト自体が更新されますが、データベース自体は更新されません。 Appointmentの説明などの他の要素は、データベース内で正常に更新されます。開始時刻と終了時刻は異なります。

Entityクラス（これは間接的にEntityManager.merge()とデータベースで更新されます。

package mcknighte.entity; 

import java.io.Serializable; 
import java.util.Calendar; 
import java.util.List; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
import javax.persistence.ManyToOne; 
import javax.persistence.OneToMany; 
import javax.persistence.Temporal; 
import static javax.persistence.TemporalType.TIMESTAMP; 
import javax.validation.constraints.NotNull; 
import mcknighte.common.Convertable; 

/** 
* Appointment entity class, to represent an Appointment within the database 
* and throughout the application 
* 
* @author Edward McKnight (UP608985) 
* @see Client 
* @see AppointmentFacade 
* @see AppointmentService 
* @see AppointmentController 
* @since 2017 
* @version 1.0 
*/ 
@Entity 
public class Appointment implements Serializable, Convertable { 
    private static final long serialVersionUID = 1L; 
    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private Long id; 
    @NotNull 
    @Temporal(TIMESTAMP) 
    private Calendar startTime; 
    @NotNull 
    @Temporal(TIMESTAMP) 
    private Calendar endTime; 
    @NotNull 
    private String description; 
    @NotNull 
    @ManyToOne(targetEntity = Client.class) 
    private Client creator; 
    @NotNull 
    @OneToMany(targetEntity = Client.class) 
    private List<Client> attendees; 

    /** 
    * Constructor 
    */ 
    public Appointment() { 
     this.startTime = Calendar.getInstance(); 
     this.endTime = Calendar.getInstance(); 
    } 

    /** 
    * Get the attendees for the appointment 
    * 
    * @return a list of attendees for the appointment 
    */ 
    public List<Client> getAttendees() { 
     return attendees; 
    } 

    /** 
    * Set the attendees for the appointment 
    * 
    * @param attendees a list of attendees for the appointment 
    */ 
    public void setAttendees(List<Client> attendees) { 
     this.attendees = attendees; 
    } 

    /** 
    * Get the creator of the appointment 
    * 
    * @return the creator of the appointment 
    */ 
    public Client getCreator() { 
     return creator; 
    } 

    /** 
    * Set the creator of the appointment 
    * 
    * @param creator the creator of the appointment 
    */ 
    public void setCreator(Client creator) { 
     this.creator = creator; 
    } 

    /** 
    * Get the description for the appointment 
    * 
    * @return the description for the appointment 
    */ 
    public String getDescription() { 
     return description; 
    } 

    /** 
    * Set the description for the appointment 
    * 
    * @param description the description for the appointment 
    */ 
    public void setDescription(String description) { 
     this.description = description; 
    } 

    /** 
    * Get the end time of the appointment 
    * 
    * @return the end time of the appointment 
    */ 
    public Calendar getEndTime() { 
     return endTime; 
    } 

    /** 
    * Set the end time of the appointment 
    * 
    * @param end the end time of the appointment 
    */ 
    public void setEndTime(Calendar end) { 
     this.endTime = end; 
    } 

    /** 
    * Get the start time of the appointment 
    * 
    * @return the start time of the appointment 
    */ 
    public Calendar getStartTime() { 
     return startTime; 
    } 

    /** 
    * Set the start time of the appointment 
    * 
    * @param start the start time of the appointment 
    */ 
    public void setStartTime(Calendar start) { 
     this.startTime = start; 
    } 

    /** 
    * Get the ID for the appointment 
    * 
    * @return the ID for the appointment 
    */ 
    @Override 
    public Long getId() { 
     return id; 
    } 

    /** 
    * Set the ID for the appointment 
    * 
    * @param id the ID for the appointment 
    */ 
    public void setId(Long id) { 
     this.id = id; 
    } 

    /** 
    * Hash code 
    * 
    * @return int 
    */ 
    @Override 
    public int hashCode() { 
     int hash = 0; 
     hash += (id != null ? id.hashCode() : 0); 
     return hash; 
    } 

    /** 
    * Equals 
    * 
    * @param object the object to compare to 
    * @return whether or not this equals the object being compared to 
    */ 
    @Override 
    public boolean equals(Object object) { 
     if (!(object instanceof Appointment)) { 
      return false; 
     } 
     Appointment other = (Appointment) object; 
     return !((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))); 
    } 

    /** 
    * Represent this object as a string 
    * 
    * @return a string representation of this object 
    */ 
    @Override 
    public String toString() { 
     return "mcknighte.entity.Appointment[ id=" + id + " ]"; 
    } 

} 

Answer 1

問題が解決されましたanother StackOverflow questionを見つけ、Oracle documentationを読んだ後に行われるために必要なすべての

ました。 Dateととして、Calendar特性の各々に@Mutableアノテーションを追加します210はデフォルトでは不変です。