java.sql.Timestamp extends java.util.Date. You can do:

String s = new SimpleDateFormat("MM/dd/yyyy").format(myTimestamp);

Or to also include time:

String s = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss").format(myTimestamp);

You can do it the same way as a java.util.Date (since java.sql.Date is a sub-class of java.util.Date) with a SimpleDateFormat

SimpleDateFormat sdf = new SimpleDateFormat(
    "MM-dd-yyyy");
int year = 2014;
int month = 10;
int day = 31;
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month - 1); // <-- months start
                                    // at 0.
cal.set(Calendar.DAY_OF_MONTH, day);

java.sql.Date date = new java.sql.Date(cal.getTimeInMillis());
System.out.println(sdf.format(date));

Output is the expected

10-31-2014

Can't your SQL server accept strings for dates? The ones I've used can, so I just do something like:

String sqlDate = new SimpleDateFormat("yyyy-MM-dd").format(new SimpleDateFormat("dd-MM-yyyy").parse(startDate));

... and pass sqlDate to the parametrized query. Like konrad mentioned, lowercase 'mm' is for minutes, and uppercase 'MM' is for month, so I think that's where your problem was.

If your database is Oracle, you can change your prepared statement so that it includes a TO_DATE call instead of the date itself.

So, if your current insert statement is something like

String sql = "INSERT INTO foo (datefield) VALUES (?)";
PreparedStatement stmt = con.prepareStatement(sql);

And you use something like stmt.setDate(1,sqldt) to fill in the value, then you can change it into something like

String sql ="INSERT INTO foo (datefield) VALUES (TO_DATE(?,?))";
PreparedStatement stmt = con.prepareStatement(sql);

And use

String oracleFormat = "mm/dd/yyyy"; // Not hard-coded in real life
String dateStr = "03/09/2017";      // Not hard-coded in real life
stmt.setString(1,dateStr);
stmt.setString(2,oracleFormat);
stmt.executeUpdate();

In this case, Oracle will convert the string into a date for you, instead of having Java do that.

Pay attention to changing all the other parameter numbers to fit.