ClassCast exception while iterating over an element collection of embeddables

When I try to iterate over a collection of embeddable objects, I get the
following exception:

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to
com.kryterion.wa.core.model.ftp.FtpSubdirectory

I'm very confused by this...I have the Pro JPA 2 book and closely followed
its example of the Employee class and its element collection of embeddable
Vacation bookings.

When I look at the collection while debugging, I see that the subdirectories
field is an ArrayList proxy which has a field called elementData, which is
an Object array. When I inspect the first element of this Object array, I
see that it too is an Object array with three string elements (the path,
type, and description values). Basically, I don't see that OpenJPA loaded up
a collection of FtpSubdirectory objects as I would've expected, and hence
the class cast exception.

My mappings:

@Entity
@Table(name = "core_ftp_connection")
public class FtpConnection extends AbstractMultiNamedEntity {
    
    private static final long serialVersionUID = 1L;

...    
    
    @ElementCollection(targetClass = FtpSubdirectory.class, fetch =
FetchType.EAGER)
    @CollectionTable(name = "core_ftp_subdir", joinColumns =
@JoinColumn(name = "fk_ftp_connection_id"))
    private Collection<FtpSubdirectory> subdirectories = new
ArrayList<FtpSubdirectory>();
...

and

@Embeddable
public class FtpSubdirectory {
    
    @Column(name = "path")
    private String path;
    
    @Column(name = "type")
    @Enumerated(EnumType.STRING)
    private SubdirectoryType type;
    
    @Column(name = "description")
    private String description;
    
    public String getPath() {
        return path;
    }
...

Mark -

Can we see the code that shows how you are getting a FtpConnection? Also,
what version of OpenJPA are you running and how are you enhancing your
Entities?

One note, I'm pretty certain you can get rid of the 'targetClass =
FtpSubdirectory.class' attribute of your ElementCollection annotation.

Thanks,
RickOn Fri, Jun 22, 2012 at 8:18 PM, markyo  wrote:

> When I try to iterate over a collection of embeddable objects, I get the
> following exception:
>
> java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to
> com.kryterion.wa.core.model.ftp.FtpSubdirectory
>
> I'm very confused by this...I have the Pro JPA 2 book and closely followed
> its example of the Employee class and its element collection of embeddable
> Vacation bookings.
>
> When I look at the collection while debugging, I see that the
> subdirectories
> field is an ArrayList proxy which has a field called elementData, which is
> an Object array. When I inspect the first element of this Object array, I
> see that it too is an Object array with three string elements (the path,
> type, and description values). Basically, I don't see that OpenJPA loaded
> up
> a collection of FtpSubdirectory objects as I would've expected, and hence
> the class cast exception.
>
> My mappings:
>
> @Entity
> @Table(name = "core_ftp_connection")
> public class FtpConnection extends AbstractMultiNamedEntity {
>
>    private static final long serialVersionUID = 1L;
>
> ...
>
>    @ElementCollection(targetClass = FtpSubdirectory.class, fetch =
> FetchType.EAGER)
>    @CollectionTable(name = "core_ftp_subdir", joinColumns =
> @JoinColumn(name = "fk_ftp_connection_id"))
>    private Collection<FtpSubdirectory> subdirectories = new
> ArrayList<FtpSubdirectory>();
> ...
>
> and
>
> @Embeddable
> public class FtpSubdirectory {
>
>    @Column(name = "path")
>    private String path;
>
>    @Column(name = "type")
>    @Enumerated(EnumType.STRING)
>    private SubdirectoryType type;
>
>    @Column(name = "description")
>    private String description;
>
>    public String getPath() {
>        return path;
>    }
> ...
>

Hi Rick,

I'm using OpenJPA 2.2.0 and build-time enhancement. The ftp connection is 
getting retrieved eagerly as a member of a ClientRegion object:

@Entity
@Table(name = "client_region")
public class ClientRegion extends AbstractNamedEntity {
    
    private static final long serialVersionUID = 1L;
    
    public static final String FIND_ALL_BY_CLIENT_NAME_QUERY = 
"ClientRegion.findAllByClientName";
    public static final String CLIENT_NAME_QUERY_PARAM = "clientName";
    public static final String STATUS_QUERY_PARAM = "status";
    
    @Enumerated(EnumType.STRING)
    @Column(name = "STATUS")
    private Status status = ACTIVE;
    
    @ManyToOne
    @JoinColumn(name = "fk_client_id")
    private Client client;
    
    @Column(name = "brand")
    private String brand;
    
    @ManyToMany(cascade = {
            CascadeType.MERGE, CascadeType.PERSIST
    }, fetch = FetchType.EAGER)
    @JoinTable(name = "core_client_ftp_connection", joinColumns = 
@JoinColumn(name = "fk_client_region_id"), inverseJoinColumns = 
@JoinColumn(name = "fk_ftp_connection_id"))
    private Collection<FtpConnection> ftpConnections = 
new ArrayList<FtpConnection>();

....

I'm using Spring Data JPA to access the objects.

I appreciate your help on this.



Mark

Mark -

Is there any way that you could put together a small standalone unit test
that recreates this issue? I am unable to put a test together that
demonstrates the ClassCastException.

Thanks,
RickOn Fri, Jul 20, 2012 at 9:05 PM, Mark Youwanes wrote:

> Hi Rick,
>
> I'm using OpenJPA 2.2.0 and build-time enhancement. The ftp connection is
> getting retrieved eagerly as a member of a ClientRegion object:
>
> @Entity
> @Table(name = "client_region")
> public class ClientRegion extends AbstractNamedEntity {
>
>     private static final long serialVersionUID = 1L;
>
>     public static final String FIND_ALL_BY_CLIENT_NAME_QUERY =
> "ClientRegion.findAllByClientName";
>     public static final String CLIENT_NAME_QUERY_PARAM = "clientName";
>     public static final String STATUS_QUERY_PARAM = "status";
>
>     @Enumerated(EnumType.STRING)
>     @Column(name = "STATUS")
>     private Status status = ACTIVE;
>
>     @ManyToOne
>     @JoinColumn(name = "fk_client_id")
>     private Client client;
>
>     @Column(name = "brand")
>     private String brand;
>
>     @ManyToMany(cascade = {
>             CascadeType.MERGE, CascadeType.PERSIST
>     }, fetch = FetchType.EAGER)
>     @JoinTable(name = "core_client_ftp_connection", joinColumns =
> @JoinColumn(name = "fk_client_region_id"), inverseJoinColumns =
> @JoinColumn(name = "fk_ftp_connection_id"))
>     private Collection<FtpConnection> ftpConnections =
> new ArrayList<FtpConnection>();
>
> ....
>
> I'm using Spring Data JPA to access the objects.
>
> I appreciate your help on this.
>
>
>
> Mark
>
>
>
>
>

Sorry, I missed that you opened a JIRA already... I'll try to take a look
sometime in the coming days.On Mon, Jul 23, 2012 at 8:44 AM, Rick Curtis  wrote:

> Mark -
>
> Is there any way that you could put together a small standalone unit test
> that recreates this issue? I am unable to put a test together that
> demonstrates the ClassCastException.
>
> Thanks,
> Rick
>
>
> On Fri, Jul 20, 2012 at 9:05 PM, Mark Youwanes wrote:
>
>> Hi Rick,
>>
>> I'm using OpenJPA 2.2.0 and build-time enhancement. The ftp connection is
>> getting retrieved eagerly as a member of a ClientRegion object:
>>
>> @Entity
>> @Table(name = "client_region")
>> public class ClientRegion extends AbstractNamedEntity {
>>
>>     private static final long serialVersionUID = 1L;
>>
>>     public static final String FIND_ALL_BY_CLIENT_NAME_QUERY =
>> "ClientRegion.findAllByClientName";
>>     public static final String CLIENT_NAME_QUERY_PARAM = "clientName";
>>     public static final String STATUS_QUERY_PARAM = "status";
>>
>>     @Enumerated(EnumType.STRING)
>>     @Column(name = "STATUS")
>>     private Status status = ACTIVE;
>>
>>     @ManyToOne
>>     @JoinColumn(name = "fk_client_id")
>>     private Client client;
>>
>>     @Column(name = "brand")
>>     private String brand;
>>
>>     @ManyToMany(cascade = {
>>             CascadeType.MERGE, CascadeType.PERSIST
>>     }, fetch = FetchType.EAGER)
>>     @JoinTable(name = "core_client_ftp_connection", joinColumns =
>> @JoinColumn(name = "fk_client_region_id"), inverseJoinColumns =
>> @JoinColumn(name = "fk_ftp_connection_id"))
>>     private Collection<FtpConnection> ftpConnections =
>> new ArrayList<FtpConnection>();
>>
>> ....
>>
>> I'm using Spring Data JPA to access the objects.
>>
>> I appreciate your help on this.
>>
>>
>>
>> Mark
>>
>>
>>
>>
>>
>
>
> --
> *Rick Curtis*
>
>