Day of Month Suffix - st nd rd th

Here is a simple way to put suffix for day

String getDayOfMonthSuffix(final int n)
{
 checkArgument(n >= 1 && n <= 31), "illegal day of month: " + n);
 if (n >= 11 && n <= 13)
{
return "th";
}
 switch (n % 10)
{
 case 1: return "st";
case 2: return "nd";
 case 3: return "rd";
default: return "th";
 }
}