Value from last inserted row in DB [duplicate]

Answer 1

You should use ResultSet#getLong() instead. If in vain, try ResultSet#getRowId() and eventually cast it to oracle.sql.ROWID. If the returned hex string is actually the ID in hexadecimal flavor, then you can try converting it to decimal by Long#valueOf() or Integer#valueOf().

Long id = Long.valueOf(hexId, 16);

That said, Oracle's JDBC driver didn't support ResultSet#getGeneratedKeys() for a long time and is still somewhat troublesome with it. If you can't get that right, then you need to execute a SELECT CURRVAL(sequencename) on the same statement as you did the insert, or a new statement inside the same transaction, if it was a PreparedStatement. Basic example:

public void create(User user) throws SQLException {
    Connection connection = null;
    PreparedStatement preparedStatement = null;
    Statement statement = null;
    ResultSet generatedKeys = null;

    try {
        connection = daoFactory.getConnection();
        preparedStatement = connection.prepareStatement(SQL_INSERT);
        preparedStatement.setValue(1, user.getName());
        // Set more values here.
        int affectedRows = preparedStatement.executeUpdate();
        if (affectedRows == 0) {
            throw new SQLException("Creating user failed, no rows affected.");
        }
        statement = connection.createStatement();
        generatedKeys = statement.executeQuery(SQL_CURRVAL);
        if (generatedKeys.next()) {
            user.setId(generatedKeys.getLong(1));
        } else {
            throw new SQLException("Creating user failed, no generated key obtained.");
        }
    } finally {
        close(generatedKeys);
        close(statement);
        close(preparedStatement);
        close(connection);
    }
}

Oh, from your code example, the following line

stmt.RETURN_GENERATED_KEYS;

is entirely superfluous. Remove it.

You can find here another example which I posted before about getting the generated keys, it uses the normal getGeneratedKeys() approach.