基本属性java.sql.Blob的问题

I have this code

我有这个代码

@Entity
@Table(name = "picture")
public class Picture implements Serializable {
    @Id
    @Column(name = "id")
    @GeneratedValue
    private int id;
    @Column(name = "format", length = 8)
    private String format;

    @Basic(fetch = FetchType.LAZY)
    @Column(name = "context", nullable = true, columnDefinition="mediumblob")
    @Lob
    private java.sql.Blob myBlobAttribute; // protected accessor and modifier

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "branch_fk", referencedColumnName = "id", nullable = false)
    private Branch branch;
//Some setter and getter
@Entity
@Table(nam