Example: initials of a name using the StringBuffer class

public class SideEffect2 {
  public static void main (String[] args) {
    String s = "name surname";
    StringBuffer sbuf = new StringBuffer(s);
    sbuf.replace(0,1,s.substring(0,1).toUpperCase());
    sbuf.replace(5,6,s.substring(5,6).toUpperCase());
    System.out.println(sbuf.toString());
  }
}