Google App Engine JDO问题

Question

我试图让下面的类持久化，但是得到一个UnexpectedException。我省略了班级的后一部分。

package com.bingehopper.server;
import java.util.Date;

import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;

import com.bingehopper.client.VenueDetails;
import com.google.appengine.api.users.User;

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Venue {

  @PrimaryKey
  @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
  private Long id;
  @Persistent
  private User user;
  @Persistent
  private VenueDetails venue;
  @Persistent
  private Date createDate;

  public Venue()
  {

      this.createDate = new Date();

  }

  public Venue(User user, VenueDetails venue)
  {

      this();
      this.user = user;
      this.venue = venue;

  }
}

以下是错误日志：

com.google.appengine.tools.development.ApiProxyLocalImpl log
SEVERE: javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract void      com.bingehopper.client.VenueService.addVenue(com.bingehopper.client.VenueDetails) throws com.bingehopper.client.NotLoggedInException' threw an unexpected exception: java.lang.IllegalArgumentException: venue: com.bingehopper.client.VenueDetails is not a supported property type

VenueDetails是我在客户端软件包中创建的一个类。如果我希望它继续存在，我可以不在Venue类中使用VenueDetails对象变量吗？或者有办法使它工作？我以前没有GWT的经验，也不确定我是否正确地接近这一点。谢谢你的帮助。