When i use locks, it locks the row until transaction ends right?
Hibernate could lock reading and writing as said in documentation.

Example:

One reads the row and lock it , the transaction is still running.
Second in other transaction(internet session) tries to read or write in the row but it is locked,

1)some error is shown at this time ?!
2)The second "read or write" is kind queued ?!
3)Then when the first transaction commits , the second could "read or write"?

Thank you in advance.

The second read is queued. I don't know if Hibernate rests over the lock implementation of the database, in that case you should be careful with locks because in some databases you could be locking more than one row (pages or the entire table even).

Bye

Hibernate delegate locks to the DB