SimpleDateFormat does not recognize date in csv

> When you open the file, the date looks like 5/16/1997. However, once the file is read, the date string becomes "1997-05-16".

How can that be?

please, show your code

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

java.util.Date dd = sdf.parse("1997-05-16",new ParsePosition(0));

should work

This is tested and works without problems:

SimpleDateFormat sdf750 = new SimpleDateFormat("yyyy-MM-dd");

java.util.Date dd750 = sdf750.parse("1997-05-16",new ParsePosition(0));

        System.out.println(dd750);

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Output:

Fri May 16 00:00:00 PDT 1997

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I need this code to work w/o knowing the exact format. So I don't want to specify new SimpleDateFormat("yyyy-MM-dd");

my code for reading the csv.

try {
                  File csvFile = new File(uploadDir + filename);
                  BufferedReader bufRdr = new BufferedReader(new FileReader(csvFile));
                  String line = null;
                  int row = 0;

                  // read each line of text file
                  while ((line = bufRdr.readLine()) != null) {
                        List<String> oneLine = new ArrayList<String>();
                        StringTokenizer st = new StringTokenizer(line, ",");
                        while (st.hasMoreTokens()) {
                              // get next token and store it in the array
                              oneLine.add(st.nextToken());
                        }
                        if (row==0){
                              headers = oneLine;
                        } else {
                              dataLines.add(oneLine);
                        }
                        row++;
                  }
                  bufRdr.close();
                  return buildRecords(headers, dataLines);
            } catch (Exception ex) {
                  ex.printStackTrace();
            }

In this way you can test any number of formats,
but still you need to be sure that date will follow at least
one of the expected formats:

SimpleDateFormat sdf750 = new SimpleDateFormat("yyyy-MM-dd");
 SimpleDateFormat       sdf751 = new SimpleDateFormat("yyyy/MM/dd");

        sdf750.setLenient(false);
        String dateString = "1997/05/16";

java.util.Date dd750 = sdf750.parse(dateString,new ParsePosition(0));

         if(dd750 == null) {
             System.out.println(" trying again");
                dd750 = sdf751.parse(dateString,new ParsePosition(0));
         }

        System.out.println(dd750);

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Output:

 trying again
Fri May 16 00:00:00 PDT 1997

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You actually should setLenient(false) on all SimpleDateFormat instances whoch you would use, so better add one more setLenient(false) like here:

SimpleDateFormat sdf750 = new SimpleDateFormat("yyyy-MM-dd");
 SimpleDateFormat       sdf751 = new SimpleDateFormat("yyyy/MM/dd");

        sdf750.setLenient(false);
        sdf751.setLenient(false);
        String dateString = "1997/05/16";

java.util.Date dd750 = sdf750.parse(dateString,new ParsePosition(0));

         if(dd750 == null) {
             System.out.println(" trying again");
                dd750 = sdf751.parse(dateString,new ParsePosition(0));
         }

        System.out.println(dd750);

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Yes, I tested, and created the csv file with these dates, which I enetred with Notrpad:

abc,1,03-05-1997
def,3,11-03-2002


when I opened this csv file in Excel,
Excel showed dates with slashes

03/05/1997
11/3/2002


It is definitel the Excel which transfroms the way the date is shown.

So when you read .csv file with java you program will of couse read it as they sit in the csv
file
03-05-1997
Open your file with Notepad - and that's how your java program will see everything in the file.
Don't open in excel - it becomes misleading, as Excle makes transformation of its own

This comment - "You cannot parse the date without knowing the foramt" was not true. it will parse some common date patterns successfully even if you never fed it any pattern, just not the unusual pattern "yyyy-MM-dd".

The case about the internal format differing from Excel display was true.

I ended out listing all possible date patterns I might run into, as suggested by one of the experts.