For Jim’s email, invoke this method:
public static String email(String firstname, String lastname) {
final char AT = '@';
StringBuilder sb = new StringBuilder();
sb.append(Character.toLowerCase(firstname.charAt(0)))
.append('.')
.append(lastname.toLowerCase())
.append(AT).append("ku.th");
return sb.toString();
}
//TODO Modify algorithm to work for Thai names, too.
When you need to join or modify Strings, a StringBuilder (as above) is more efficient than using Strings. Stringbuilder is mutable (the methods modify the StringBuilder object) while Strings are immutable (every operation creates a new String).