Chapter 6: Database

try (var conn = DriverManager.getConnection(jdbcUrl, user, pass);
     var ps = conn.prepareStatement("SELECT name FROM users WHERE id=?")) {
    ps.setLong(1, id);
    try (var rs = ps.executeQuery()) {
        if (rs.next()) return rs.getString(1);
    }
}
return null;

Use PreparedStatement for all external input. Pool connections with HikariCP in production.