why cant not delete a segment by api , please

[????????]

String deleteUrl = 
"http://192.168.35.2:7070/kylin/api/cubes/F_CUBE/segs/20170113000000_20170114000000";;
Map<String,Object> map = new HashMap<String,Object>();
map.put("username", "ADMIN");
map.put("password", "KYLIN");
//still not work as
//map.put("Authorization", "Basic QURNSU46S1lMSU4=");
doDelete(deleteUrl,map);
 _________
  public static void doDelete(String urlStr,Map<String,Object> paramMap) throws 
Exception{
        String paramStr = prepareParam(paramMap);
        if(paramStr == null || paramStr.trim().length()<1){
            
        }else{
            urlStr +="?"+paramStr;
        }   
        System.out.println(urlStr);
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestMethod("DELETE");
        if(conn.getResponseCode() ==200){
            System.out.println("????");
        }else{
            System.out.println(conn.getResponseCode());// always print 505 or 
401
        }
    }