Date Calculations

import java.text.FieldPosition;

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

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.*;
 
public class JDate {
 
 private static SimpleDateFormat sdfNormal = new SimpleDateFormat("dd/MM/yyyy");
  
 
 private static SimpleDateFormat sdfNormalUs = new SimpleDateFormat("MM/dd/yyyy");
 private static SimpleDateFormat sdfSQL = new SimpleDateFormat("yyyy-MM-dd");
 private static FieldPosition fpDate = new FieldPosition(SimpleDateFormat.DATE_FIELD);
 private static FieldPosition fpDate1 = new FieldPosition(SimpleDateFormat.YEAR_FIELD);
 private static SimpleDateFormat sdfTime = new SimpleDateFormat("S");
 
 static
 {
  sdfNormal.setLenient(false);
  sdfSQL.setLenient(false);
  sdfNormalUs.setLenient(false);
 }
 
 public static String toNormalDate(String str) throws ParseException
 {
  if(str==null)
  {
   str = "";
   return str;
  }
  StringBuffer sb = new StringBuffer();
  Date dt = sdfSQL.parse(str);
  sdfNormal.format(dt,sb,fpDate);
  return sb.toString();
 }
 
 public static String toSQLDate(String str) throws ParseException
 {
  if(str=="")
  {
   str = null;    
   return str;    
  }
  StringBuffer sb = new StringBuffer();
  Date dt = sdfNormal.parse(str);
  sdfSQL.format(dt,sb,fpDate);
  return sb.toString();
 }
 public static String parseSQLDateToUSDate(String str) throws ParseException
 {
  if(str=="")
  {
   str = null;    
   return str;    
  }
  StringBuffer sb = new StringBuffer();
  Date dt = sdfSQL.parse(str);
  sdfNormalUs.format(dt,sb,fpDate1);
  return sb.toString();
 }
 
 public static String getElapsedTime(Date date_start, Date date_end)
 {
  long start_ms = date_start.getTime();
  long end_ms = date_end.getTime();
  long total_ms = end_ms - start_ms;      
     long total_sec = (total_ms - (total_ms%1000))/1000;     
     long total_min = total_sec / 60;     
     long total_hr = total_min / 60;

  long rem_ms = total_ms % 1000;  
  long rem_sec = total_sec % 60;  
  long rem_min = (total_min) % 60;  
  long rem_hr = total_min / 60;

  String rem_time = ""+ rem_hr + "Hr:" + rem_min + "Min:" + rem_sec + "Sec:" + rem_ms +"Ms";
  return rem_time;  
 }
 
 public static String getTimeString(Date date_string)
 {
  String s_time = ""+ date_string.getHours();
  s_time = s_time +  "Hr:" + date_string.getMinutes();
  s_time = s_time +  "Min:" + date_string.getSeconds();
  s_time = s_time +  "Sec:" + (date_string.getTime() % 1000)+ "Ms";
  return s_time;
 }
 
 public static Date parseStringToDate(String s_date,String s_split){
     int i_year=0,i_month=0,i_date=0;
     
     if(s_split.equals("-")){
         String s_tokens[] = s_date.split("-");
     
         i_year = Integer.parseInt(s_tokens[0]);
         i_month = Integer.parseInt(s_tokens[1]);
         i_date = Integer.parseInt(s_tokens[2]);
     }
     if(s_split.equals("/")){
         String s_tokens[] = s_date.split("/");
     
         i_year = Integer.parseInt(s_tokens[2]);
         i_month = Integer.parseInt(s_tokens[1]);
         i_date = Integer.parseInt(s_tokens[0]);
     }    
     
     Date dt_parsed = new Date(i_year-1900, i_month-1, i_date);
     return dt_parsed;
 }
 
 public static String parseUSDateToNormalDate(String s_date){
      String s_tokens[] = s_date.split("/");
     
      String s_month = s_tokens[0];
      String s_day = s_tokens[1];
      String s_year = s_tokens[2];
      
      String s_normal_date = s_day+"/"+s_month + "/"+ s_year;
      return s_normal_date;
 }

 
 public static void main(String[] args) 
 {
  String strSQL = "1983-03-31";
  String strNormal = "21/11/1983";
  String prop_path = JLogger.getlog4JPropertyPath();
      
      PropertyConfigurator.configure(prop_path);
      
      //Logger log = Logger.getLogger(Constants.POPUPQUERY_CLASS); 
   
        // log.setLevel(Level.DEBUG);
  
  try
  {
   
  }
  catch(Exception ex)
  {
   //JLogger.log(-1,ex.toString(),ex);
  //log.debug(MessageConstants.EXCEPTION_ROLLBACK);
  }
 }
 
  public static String calcGMTTime()
     {
       /*double d_offset=8; //Maleshiian offset later value will come from propertyu file. 
      
         Date date_current = new Date();
         
         long l_utc = date_current.getTime() + (date_current.getTimezoneOffset() * 60000);      
         
         Date date_sys = new Date(l_utc +Math.round(3600000*d_offset));
         
         //System.out.println("..."+date_sys.toLocaleString());
         
         return  date_sys.toLocaleString();*/
      
       Date d = new Date();
         
       //System.out.println("befor date is :" +d.toString());
      
         //d.setHours(d.getHours()+12);
         d.setHours(d.getHours()-2);
         
         //String x=d.setHours(d.getHours()+12);   
         //String y=x.s
         //System.out.println("after date is :" +d);
         
         return d.toLocaleString();

     }
 
}