TwilioSMS smsAPI = TwilioSMS.create(accountSID, authToken, fromPhone);
ActivationForm.create("Signup").
        show(s -> Log.p(s), smsAPI);

ActivationForm.create("Signup").
        codeDigits(5). // number of digits in the activation code sent via SMS
        enterNumberLabel(string). // text of the label above the number input
        includeFab(true). // true if a fab should be shown, by default a fab button will appear in Android only
        includeTitleBarNext(true). // true if a next arrow should appear in the title, by default this would appear in non-Android platforms
        show(s -> Log.p(s), smsAPI);

private static final CaseInsensitiveOrder cio = new CaseInsensitiveOrder();
class Country implements Comparable<Country> {
    public final String name;
    public final String code;
    public final String flag;
    public final String isoCode2;
    public final String isoCode3;

    public Country(String name, String code, String flag, String isoCode2, String isoCode3) {
        this.name = name;
        this.code = code;
        this.flag = flag;
        this.isoCode2 = isoCode2;
        this.isoCode3 = isoCode3;
    }

    @Override
    public int compareTo(Country o) {
        return cio.compare(name, o.name);
    }
}

ArrayList<Country> con = new ArrayList<>();
try {
    JSONParser p = new JSONParser();
    Map<String, Object> dat = p.parseJSON(new InputStreamReader(getResourceAsStream("/countries.json"))); (1)
    List<Map<String, Object>> l = (List<Map<String, Object>>)dat.get("root");
    for(Map<String, Object> m : l) { (2)
        List ll = ((List)m.get("callingCode"));
        if(ll != null && ll.size() > 0) {
            String name = (String)((Map)m.get("name")).get("common");
            String callingCode = (String)ll.get(0);
            String code = (String)m.get("cioc");
            String flag = null;
            if(code != null && code.length() > 0) {
                flag = code.toLowerCase();
            }
            String isoCode2 = (String)m.get("cca2");
            String isoCode3 = (String)m.get("cca3");
            con.add(new Country(name, callingCode, flag, isoCode2, isoCode3)); (3)
        }
    }
} catch(IOException err) {
    Log.e(err);
}

Collections.sort(con); (4)
System.out.println("private static final String[] COUNTRY_NAMES = {");
for(Country c : con) { (5)
    System.out.println("    "" + c.name + "",");
}
System.out.println("};");
System.out.println("private static final String[] COUNTRY_CODES= {");
for(Country c : con) {
    System.out.println("    "" + c.code + "",");
}
System.out.println("};");
System.out.println("private static final String[] COUNTRY_FLAGS = {");
for(Country c : con) {
    if(c.flag == null) {
        System.out.println("    null,");
    } else {
        System.out.println("    "" + c.flag + "",");
    }
}
System.out.println("};");
System.out.println("private static final String[] COUNTRY_ISO2 = {");
for(Country c : con) {
    System.out.println("    "" + c.isoCode2 + "",");
}
System.out.println("};");
System.out.println("private static final String[] COUNTRY_ISO3 = {");
for(Country c : con) {
    System.out.println("    "" + c.isoCode3 + "",");
}
System.out.println("};");