FormatFunction { public static String format(String format, Object... args) { return String.format(format, args); }  static String format(String format, Object... args); static String dateFormat(String format, Object date);  }
@Test public void format() { Assert.equals(FormatFunction.format("%04d", 12), "0012"); Assert.equals(FormatFunction.format("%04d", 12345), "12345"); }