super("invalid flag " + f + " for conversion " + c);
super("Invalid flag " + f + " for conversion " + c); if (f == null) throw new NullPointerException("Null flag value passed to constructor.");
  public FormatFlagsConversionMismatchException(String f, char c)  {    super("invalid flag " + f + " for conversion " + c);    this.f = f;    this.c = c;  }