java

Sir,I have been assigned a task where i need to insert values in two tables using hibernate and jsf.The first table is staffing table where i need to insert serial No and other details of an employee.At the same time i need to insert few values in the User table.Another task is to get the value of serial number of table staffing and place its value in the reference column of User table. My Problem is that i am able to get the serial number(value autogenerated) but not able to place its value in the reference table.following is the method where i got the serial number:

public int createStaffing(Staffing staffing){ System.out.println("sucess entering StaffingDAO"); Session session = HibernateUtil.getSessionFactory().getCurrentSession(); System.out.println("connecting to hibernate util for staffing "); Transaction tx = null; System.out.println(" Inside create staffing details !! "); int serealNo=0; try{

        tx=session.beginTransaction();
        session.save(staffing);
        serealNo = (int)staffing.getSlNo();
        tx.commit();
        System.out.println("staffing created:" + serealNo +"took out the sl no in refernceNo");

    }
    catch(HibernateException hibernateException){
        System.out.println(" Exception in creating staffing details !! ");
    }
    return serealNo;
}

following is the method where i am trying to place the serealNo,strange is that if i call a hashcode method,exact hashcode get placed in the reference column,but if i try to call the above method in a different class to get the value of serial number, null pointer exception is shown.please help.following is the method where i need to call the above method,i have writen hashcode as only hashcode value gets inserted in the correct column with the following code.but shows error where try call the above method.please help as how to call the return value of the above method in the reference column.

public int createUsers(Users users){ System.out.println("sucess entering UsersDAO"); Session session = HibernateUtil.getSessionFactory().getCurrentSession(); System.out.println("connecting to hibernate util"); Transaction tx = null; System.out.println(" Inside create users details !! "); StaffingDao staff=new StaffingDao();

    staff.getClass();


    int slNo=staff.hashCode();

    try{

        tx=session.beginTransaction();

        session.save(users);


            System.out.println("got sl no in registor Dao");

                        slNo = (int)users.setSlNo(slNo);

        tx.commit();
        System.out.println("users created");
    }
    catch(HibernateException hibernateException)
    {
        System.out.println(" Exception in creating users details !! ");
    }

return slNo;

}