Here is a code that converts string date to long.

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ConvertStringDateToLong {
  public static void main(String[] args) throws Exception {
    String today = "Aug 31, 2012 19:23:17.907339000 IST";

    DateFormat formatter = new SimpleDateFormat("MMM dd, yyyy HH:mm:ss.S z");
    Date date = formatter.parse(today);
    long dateInLong = date.getTime();

    System.out.println("date = " + date);
    System.out.println("dateInLong = " + dateInLong);
  }
}

Thank you for your post. The output dateInLong gives millisecond but i want nanosecond long value for the exact date "Aug 31, 2012 19:23:17.907339000 IST" how can i do..?