BigDate g = new BigDate ( yyyy, mm , dd + 1, BigDate.NORMALIZE );
yyyy = g.getYYYY();
mm = g.getMM();
dd = g.getDD();

// This second way is more verbose,
// but it does a check that yyyy, mm, dd are valid and executes slightly faster.
BigDate g = new BigDate ( yyyy, mm , dd );
g.setOrdinal(g.getOrdinal() + 1);
yyyy = g.getYYYY();
mm = g.getMM();
dd = g.getDD();