How do a check that a string contains a valid date?

Use the parse() method of the SimpleDateFormat class, it will throw an exception if the string does not contain a valid date. Use setLenient(false) to force strict parsing.

DateFormat dateFormat = new SimpleDateFormat("dd/MM/yy");
dateFormat.setLenient(false);
try
{
Date d = dateFormat.parse("01/05/06");

// string contains valid date
}
catch (ParseException ex)
{
// string contains invalid date
}

try
{
Date d = dateFormat.parse("99/88/06");

// string contains valid date
}
catch (ParseException ex)
{
// string contains invalid date
}