private void append(PrintWriter pw,final String k,final String v){
  if (v != null) {
    pw.println(k + ": " + v);
  }
}

private void append ( PrintWriter pw , final String k , final String v ) { if ( v != null ) { pw . println ( k + ": " + v ) ; } }
appends ' k : v ' to pw if v is non null .
