I have some problem with inserting a blob field.

field declaration:
....
private byte[] b_data=new byte[]{};
....

field mapping:
....
<property column="b_data" name="b_data" type="java.sql.Blob"/>
....

insering:
....
Revision r = new Revision();
r.setI_entity(new Long(1));
r.setI_operation(new Long(1));
r.setI_record(new Long(1));
r.setB_data("1111".getBytes());
HibernateUtil.currentSession().save(r);
....

Exception:
Exception in thread "main" java.lang.ClassCastException: [B cannot be cast to java.sql.Blob
.....

Why?????