how to compare two dates in java in a simple way

I'd suggest you to use Joda library. Using the date info you have, create DateTime instances and call isBefore() method to determine which one comes first.

I would check the documentation, which shows that Date implements Comparable<Date> and so

date1.compareTo(date2);

will do what you want. You may wish to ensure that date1 is not null.

If your dates are (in fact) Strings, then use SimpleDateFormat's parse() method to convert from strings to dates, and then perform that comparison.

As others have suggested, Joda is a better date/time library (better API and threading performance).

Date d1, d2; This returns greatest dates: d1.after(d2) ? d1 : d2;

first parse the string into a Date object using a SimpleDateFormat :

String dateStringA = "Wed, 31 Jul 2013 09:31:51";
String dateStringB = "Mon, 05 Aug 2013 10:18:24";
SimpleDateFormat parserSDF = new SimpleDateFormat("EEE, DD MMM yyyy HH:mm:ss");
Date dateA = parserSDF.parse(dateStringA);
Date dateB = parserSDF.parse(dateStringB);
if (dateA.compareTo(dateB) > 0) {
    System.out.println("A bigger");
}

then compare the Date objects using compareTo method

You can use Date's getTime() method and then use < >.

This will work for you

  DateFormat df=new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss");
    Date date1=df.parse("Wed, 31 Jul 2013 09:31:51");
    Date date2=df.parse("Mon, 05 Aug 2013 10:18:24");
    System.out.println(date1.after(date2) ? date1 : date2);