String () { final Int2IntMap histo = collectProbeLengthsHistogram(); final int sum = histo.values().intStream().sum(); return histo.keySet().intStream() .sorted() .mapToObj(len -> String.format("%3d: %4d (%4.1f%%)", len, histo.get(len), histo.get(len) * 100.0 / sum)) .collect(joining("\n")); }