Cfrgtkky

I have a select statement that loads in the class Folders with a one-to-many relationship with File. While this sometimes happens without error, it sometimes gives me a Hibernate error saying that my use of session is unsafe, or that there were two representations of the same collection Folders.file. What am I doing wrong? Thanks for your help!

Folders.java

   @Entity

   @Table(name= "folders")



   public class Folders implements Serializable{

    private static final long serialVersionUID = 1L;



    @Id

    @Column(name = "folder_code")

    private Integer folderCode;



    @Column(name = "assign_code")

    private Integer assignCode;



    public Set<File> getFile() {

        return file;

    }





    public void setFile(Set<file> assignments) {

        this.file = file;

    }





    @OneToMany(targetEntity=File.class,cascade=CascadeType.ALL,fetch=FetchType.EAGER)

    @JoinColumn(name="assign_code",referencedColumnName="assign_code")

    Set<Folder> folder;



    public Integer getAssignCode() {

        return assignCode;

    }





    public void setAssignCode(Integer assignCode) {

        this.assignCode = assignCode;

    }



    public Integer getFolderCode() {

        return folderCode;

    }



    public void setFolderCode(Integer folderCode) {

        this.folderCode = folderCode;

    }



    public Date retrieveFileStartDate(){

        List<File> file;

        if(this.getFile()!=null){

            file= new ArrayList<File>(this.getFile());

        }else{

            file = new ArrayList<File>();

        }

        return file.size()>0 ? new 

        Date(file.get(0).getStartDate()): null;

    }







}

File.java

@Entity

@Table(name= "file")



public class File implements Serializable{

    private static final long serialVersionUID = 1L;



    @Id

    @Column(name = "assign_code")

    private Integer assignCode;





    @Column(name = "start_date")

    private String startDate;



    @Column(name = "end_date")

    private String endDate;





    public Integer getAssignCode() {

        return assignCode;

    }





    public void setAssignCode(Integer assignCode) {

        this.assignCode = assignCode;

    }





    public String getStartDate() {

        return startDate;

    }





    public void setStartDate(String startDate) {

        this.startDate = startDate;

    }





    public String getEndDate() {

        return endDate;

    }





    public void setEndDate(String endDate) {

        this.endDate = endDate;

    }







}

I am not sure about the error you are getting but looking at your entities i can say that relationship mapping is not correct.

You are mapping @OneToMany in Folder entity but what about @ManyToOne in File entity?

also define mappedBy attribute to make it work expected.

Folder.java

@OneToMany(targetEntity=File.class,cascade=CascadeType.ALL,fetch=FetchType.EAGER,mappedBy="file")

@JoinColumn(name="assign_code",referencedColumnName="assign_code")

Set<Folder> folder;

File.java

@ManyToOne

private File file;

//getter and setter