Detaching managed entity from entitymanager.
This code will detach a entity from hibernate Entitymanger making it thus unmanaged entity. // Prepare workbook object to be used for cloning. Session session = (Session) entityManager.getDelegate(); session.evict(workbook); // same as detached workbook.setId(null);// Prepare workbook object to be used for cloning. Session session = (Session) entityManager.getDelegate(); session.evict(workbook); // same as detached workbook.setId(null);