how do you handle and parse JPA persistence exceptions to provide meaningfull message to user

Question

I am fairly new to JPA and want to find best practices when handling persistence exceptions from JPA for things like say, unique constraint violations which can be

Answer 1

I'm doing something similar in my DB service layer to figure out whether the exception was caused by a conflicting constraint or general DB failure:

try {
....
} catch (final PersistenceException e) {
    final Throwable cause = e.getCause();
    if (cause instanceof MySQLIntegrityConstraintViolationException) {
        throw new ConflictException(cause);
    }
    throw new ServiceException(e);
}