Adding new Task - API dont take the date

Adding new Task - API dont take the date

Hello guys,

i have implemented the zoho api in my java program.

My Problem is adding the taskdate and the duration over the my program.  date format is  date MM-dd-yyyy and the duration is only integer, right?
My program add the tasks, but without Startdate and the duration. Can someone help me?
By the way, adding milestones with this date format work correctly.

snapshot controller:

public String addTask(String todotask, String taskdate,String taskduration,String percentcomplete,String priority){
String output = "";
try{
output=sendRequest("https://projectsapi.zoho.com/portal/"+PORTAL+"/api/private/json/task/add" 
,"authtoken="+AUTH+"&projId=aa52ac0817767c13162d454ea28097fb6755b1c1035e80e0"+"&listId=aa52ac0817767c13162d454ea28097fbb3711e3d6848763c"+"&personresponsible=105df32e30f62456b2cb84e94a5990d8"+
"&todotask="+todotask+"&taskstartdate="+taskdate+"&taskduration="+taskduration+
"&percentcomplete="+percentcomplete+"&priority="+priority);
}catch(Exception e){
System.out.println("Fehlerhafte Eingabe!");
}
return output;
}