Get auto-generated id after insert using Java JDBC [duplicate]

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This question already has answers here:

Is there a way to retrieve the autoincrement ID from a prepared statement (5 answers)

How to get Statement.getGeneratedKeys working (1 answer)

Closed 35 mins ago.

How do I get the auto generated id after I insert a new row into a table? Currently I'm doing this but does not work:

String query = "INSERT INTO user (firstname, lastname) VALUES (?,?)";
    PreparedStatement pstatement = null;
    try {
        pstatement = connection.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);

        pstatement.setString(1, firstname);
        pstatement.setString(2, lastname);
        pstatement.executeUpdate();
        ResultSet result = pstatement.getGeneratedKeys();
        int userId = 0;
        if (result.next()) {
            userId = result.getInt("id");
        }

    } catch (SQLException e) {
        throw new SQLException(e);
    } finally {
        pstatement.close();
    }

It gives me the following error: Column 'id' not found, but the table 'user' has the column 'id', which is auto incremented.