static public Timestamp addMinutess(Timestamp dateTime,int offset){
  if (dateTime == null)   dateTime=new Timestamp(System.currentTimeMillis());
  if (offset == 0)   return dateTime;
  GregorianCalendar cal=new GregorianCalendar();
  cal.setTime(dateTime);
  cal.add(Calendar.MINUTE,offset);
  return new Timestamp(cal.getTimeInMillis());
}

static public Timestamp addMinutess ( Timestamp dateTime , int offset ) { if ( dateTime == null ) dateTime = new Timestamp ( System . currentTimeMillis ( ) ) ; if ( offset == 0 ) return dateTime ; GregorianCalendar cal = new GregorianCalendar ( ) ; cal . setTime ( dateTime ) ; cal . add ( Calendar . MINUTE , offset ) ; return new Timestamp ( cal . getTimeInMillis ( ) ) ; }
return datetime + offset in minutes
