To validate a date using SimpleDateFormat in Java, you can follow these steps:

Create a SimpleDateFormat object with the desired date format. For example:

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Set the SimpleDateFormat object's lenient property to false. This will enable the strict parsing of dates.
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sdf.setLenient(false);

Parse the date string using the SimpleDateFormat object’s parse() method.

Date date = sdf.parse("23/06/2022");

If the date string is invalid, the parse() method will throw a ParseException. You can catch this exception and handle it accordingly.

try {
Date date = sdf.parse("23/06/2022");
} catch (ParseException e) {
// handle invalid date
}

Alternatively, you can use the parse() method that takes an additional ParsePosition argument, which allows you to check whether the entire string was successfully parsed or not.

ParsePosition pos = new ParsePosition(0);
Date date = sdf.parse("23/06/2022", pos);
if (pos.getErrorIndex() != -1) {
// handle invalid date
}