final String CLIENT_OPTION = "custom_client_option"; // prefix should be known from server config
try (Client client = newClient().serverSetting(CLIENT_OPTION, "opt1").build()) {

final List<GenericRecord> clientOption = client.queryAll("SELECT getSetting({option_name:String})",
        Collections.singletonMap("option_name", CLIENT_OPTION));

Assert.assertEquals(clientOption.get(0).getString(1), "opt1");

QuerySettings querySettings = new QuerySettings();
querySettings.serverSetting(CLIENT_OPTION, "opt2");

final List<GenericRecord> requestOption = client.queryAll("SELECT getSetting({option_name:String})",
        Collections.singletonMap("option_name", CLIENT_OPTION), querySettings);

Assert.assertEquals(requestOption.get(0).getString(1), "opt2");
}

Properties properties = new Properties();
properties.put(DriverProperties.serverSetting("custom_option"), "opt1");

try (Connection connection = getJdbcConnection(properties)) {
    try (Statement stmt = connection.createStatement(); ResultSet rs = stmt.executeQuery("SELECT getSetting('custom_option')")){

        assertTrue(rs.next());
        assertEquals(rs.getString(1), "opt1");
    }
}