Re: question about casting

Hi,

Hibernate uses proxies in collections when the objects were loaded from DB. Do not cast to ArrayList, cast instead to List. See http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch07.html#collections-persistent

Juan

2014-04-15 8:24 GMT-03:00 Leung <leung1_2000@yahoo.com>:

Hi,

Can you please explain the casting rule on this example? Why does it cause exception?

Thanks

The userProfileDO is the object extracted from database through hibernate

ArrayList<Contact> tmpContactList = (ArrayList<Contact>) userProfileDO.getContacts();

//warning message: List is a raw type. References to generic type List<E> should be parameterized
    public List getContacts()
    {
        return this.contacts;
    }

The above ArrayList<Contact> casting caused exception

com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract com.project.frontpage.client.serialize.UserProfile com.rentorama2.frontpage.client.rpc.Access.getUserProfile(long) throws com.project.frontpage.client.serialize.LoginServiceException' threw an unexpected exception: java.lang.ClassCastException: org.hibernate.collection.PersistentList cannot be cast to java.util.ArrayList
......

Caused by: java.lang.ClassCastException: org.hibernate.collection.PersistentList cannot be cast to java.util.ArrayList
    at com.project.frontpage.server.dao.UserProfileDAO.getUserProfile(UserProfileDAO.java:250)
    at com.project.frontpage.server.impl.AccessImpl.getUserProfile(AccessImpl.java:655)

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