how to validate number of days between given from-date and to-date in java using spring framework..?

// Validation if From date field more than To Date field
function ValidateDate(){
if(isFromDateValid == true && isToDateValid == true)
{
  if(sdate>edate)
  {
    xfa.host.messageBox("'From Date'"+sdate+" is more than 'To Date'"+edate,"Dates Incompatibility",0,0);
    data.Body.SDATE.fontColor = "red";
    data.Body.EDATE.fontColor = "red";
    data.Body.days.rawValue = null;
  }
  else
  {
  // Logic to calculation of days between given dates
    var sdate1 = util.scand("yyyy-mm-dd", sdate);
    var edate1 = util.scand("yyyy-mm-dd", edate);
    for(var i=0;i<n;i++)
    {
        var sDateT = sdate1.getTime();
        var sDateD = sdate1.getDay();
        var sDateN = sDateT+(24*60*60*1000);
        if(sdate1>edate1)
        {
            break;
        }
        i = i+1;
        sdate1 = new Date(sDateN);
    }
    data.Body.days.rawValue = i;
  }
}
}