Session throws an exception, including any
SQLException, immediately rollback the database transaction, call
Session.close() and discard the
Session instance. Certain methods of
Session will not leave the session in a consistent state. No exception thrown by Hibernate can be treated as recoverable. Ensure that the
Session will be closed by calling
close() in a
HibernateException, which wraps most of the errors that can occur in a Hibernate persistence layer, is an unchecked exception. It was not in older versions of Hibernate. In our opinion, we should not force the application developer to catch an unrecoverable exception at a low layer. In most systems, unchecked and fatal exceptions are handled in one of the first frames of the method call stack (i.e., in higher layers) and either an error message is presented to the application user or some other appropriate action is taken. Note that Hibernate might also throw other unchecked exceptions that are not a
HibernateException. These are not recoverable and appropriate action should be taken.
SQLExceptions thrown while interacting with the database in a
JDBCException. In fact, Hibernate will attempt to convert the exception into a more meaningful subclass of
JDBCException. The underlying
SQLException is always available via
JDBCException.getCause(). Hibernate converts the
SQLException into an appropriate
JDBCException subclass using the
SQLExceptionConverter attached to the
SessionFactory. By default, the
SQLExceptionConverter is defined by the configured dialect. However, it is also possible to plug in a custom implementation. See the javadocs for the
SQLExceptionConverterFactory class for details. The standard
JDBCException subtypes are:
JDBCConnectionException: indicates an error with the underlying JDBC communication.
SQLGrammarException: indicates a grammar or syntax problem with the issued SQL.
ConstraintViolationException: indicates some form of integrity constraint violation.
LockAcquisitionException: indicates an error acquiring a lock level necessary to perform the requested operation.
GenericJDBCException: a generic exception which did not fall into any of the other categories.