@Override
  public String toString() {
    final StringBuilder sb = new StringBuilder("[");
    for (Object item : this) {
      if (sb.length()>1) sb.append(", ");
      if (item instanceof char[]) {
        sb.append((char[]) item);
      } else {
        sb.append(item);
      }
    }
    return sb.append(']').toString();
  }
Returns an {@link Iterator} for {@code char[]} instances in this set.
linguistics/src/main/java/com/yahoo/language/simple/kstem/CharArraySet.java