Java date to timestamp, timestamp changed to date

Package date;

Import java.text.ParseException;
Import Java.text.SimpleDateFormat;
Import Java.util.Date;

public class Test {
public static void Main (string[] args) {
Date d = new Date ();
String begindate = "1435845268096";

SimpleDateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss");

String SD = Sdf.format (New Date (Long.parselong (begindate))); Time Stamp Conversion Date
System.out.println (D.gettime ());
SYSTEM.OUT.PRINTLN (SD);
String SDT = Sdf.format (d);
SYSTEM.OUT.PRINTLN ("Current system time:" + SDT);
SYSTEM.OUT.PRINTLN ("System timestamp:" + d.gettime ());
System.out.println ("Timestamp conversion date:" + SD);
try {
SimpleDateFormat SF = new SimpleDateFormat ("Yyyy-mm-dd");
D = Sf.parse ("2015-07-03 22:20:20");//date converted to timestamp
} catch (ParseException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
Long timestemp = D.gettime ();
System.out.println ("Date conversion timestamp:" + timestemp);

Test T = new Test ();
System.out.println (">>>>>>>>>>>>>//timestamp conversion date >"
+ t.stamptotime ("1435845268096"));
System.out.println ("<<<<<<<<<<<<<<<<//date converted to timestamp <"
+ T.timetostamp ("2015-07-03"));
}

/*//Timestamp conversion date */
public string Stamptotime (string stamp) {
String sd = "";
Date d = new Date ();
SimpleDateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd");
SD = Sdf.format (New Date (Long.parselong (stamp))); Time Stamp Conversion Date
return SD;
}

/*/Date converted to timestamp */
Public long Timetostamp (String timers) {
Date d = new Date ();
Long timestemp = 0;
try {
SimpleDateFormat SF = new SimpleDateFormat ("Yyyy-mm-dd");
D = sf.parse (timers);//date converted to timestamp
} catch (ParseException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
Timestemp = D.gettime ();
return timestemp;
}
}

Java date to timestamp, timestamp changed to date