hibernate NonUniqueObjectException: a different object with the same identifier value was already associated with the session:

Question

My Code:

I am trying to do either update/insert. It gets inserted properly, only problem is when I try to update it gives below error message.

private String sessionType=null;
public String getAccountsDetails(List<Account> accountList) {       
    Session session = sessionFactory.openSession();
    for (Account account : accountList) {
        AccountDetails accountDetails = new AccountDetails();
        accountDetails.setAccountsId(Long.parseLong(account.getId()));
        accountDetails.setAccounttype(account.getAccountType().value());
        Query query = session.createQuery("from QBAccounts qba where qba.accountsId=:accId");
        List<AccountDetails> queryList = query.setParameter("accId", accountDetails.getAccountsId()).list();
        if(queryList.size()>0){         
            session.update(accountDetails);
        }else{
            session.save(accountDetails);
        }
    }
    session.flush();  
    session.beginTransaction().commit();
    session.clear();
    session.close();           
    return "Successfully data updated into table";
}

Error:

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.trinet.mulesoft.quickbooks.dto.AccountDetails#0]
    at org.hibernate.engine.StatefulPersistenceContext.checkUniqueness(StatefulPersistenceContext.java:638)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:305)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:246)        

---

EDIT 2:

I have used

session.merge(accountDetails)

there is no error, but it always does insert data into db instead of update.

Answer 1

public String getAccountsDetails(AccountDetails accountDetails) {
        System.out.println("accountDetails.accoundId-->"+accountDetails.getAccountsId());
        Session session = sessionFactory.openSession();
        Query query = session.createQuery("from QBAccounts qba where qba.accountsId=:accId");
        List<AccountDetails> queryList = query.setParameter("accId", accountDetails.getAccountsId()).list();
        session.close();
        Session session2 = sessionFactory.openSession();
//          session.saveOrUpdate(accountDetails);
        try{
            if(queryList.size()>0){                 
                session2.beginTransaction();
                /*
                 *  comment below line-50,51 to use update instead of merge, and uncomment line 53
                 */
                AccountDetails acDet = (AccountDetails) session2.get(AccountDetails.class, new Long(1));//line 50
                session2.merge(accountDetails);//line 51
                System.out.println("acDet-->"+acDet+"  --accountDetails->  "+accountDetails);//line 52
//              session2.update(accountDetails);//line 53
            }else{
                session2.beginTransaction();
                session2.save(accountDetails);
            }
        }catch(DIRException e){
            session2.getTransaction().rollback();
            System.out.println("Getting Exception : " + e.getLocalizedMessage());
        }finally{
             session2.getTransaction().commit();
             session2.close();
        }
        return "Successfully data updated into table";
    }

Removed @GeneratedValue from my dto, since value was coming from UI.

Here is the good article, how to use MERGE/UPDATE