java - Check DateInString format before formatting -

my incoming data have dates in string supposed format following format "dd/mm/yyyy". able convert date correct format with:

simpledateformat sdf = new simpledateformat("dd/mm/yyyy"); //new format  simpledateformat sdf2 = new simpledateformat("yyyy/mm/dd"); //old format string dateinstring = "2013/10/07" //string might in different format  try{   date date = sdf2.parse(dateinstring);          system.out.println(sdf.format(date)); }  catch (parseexception e){      e.printstacktrace(); } 

however, have strings in different format such 2013/10/07, 07/10/2013, 10/07/2013, 7 jul 13. how compare them before formatting individually?

i found check date format before parsing pretty similar cannot comprehend it.

thank you.

i create utility class, has list of supported formats , method tries convert given string object date.

public class dateutil {      private static list<simpledateformat> dateformats;       static {          dateformats = new arraylist<simpledateformat>();          dateformats.add(new simpledateformat("yyyy/mm/dd"));          dateformats.add(new simpledateformat("dd/m/yyyy"));          dateformats.add(new simpledateformat("dd/mm/yyyy"));          dateformats.add(new simpledateformat("dd-mmm-yyyy"));          // add more, if needed.      }       public static date converttodate(string input) throws exception {          date result = null;          if (input == null) {              return null; // or throw exception, if wish          }           (simpledateformat sdf : dateformats) {             try {                 result = sdf.parse(input);             } catch (parseexception e) {                 //caught if format doesn't match given input string             }             if (result != null) {                 break;             }          }          if (result == null) {            throw new exception("the provided date not of supported format");          }          return result;      } }