android - How to return a value from thread in java? -

in android creating thread url connection.inside thread store response message in string globally declared.when access method method returns null.

    public class rate_fetch {        string total="";           public string  rate(string dt)        {     new thread(new runnable(){            public void run(){               try  {               url url = new url(tally_ipaddr+"/prorate.jsp?plist="+sss.tostring().trim());               httpurlconnection urlconnection = (httpurlconnection) url.openconnection();              inputstream in = new bufferedinputstream(urlconnection.getinputstream());              bufferedreader r = new bufferedreader(new inputstreamreader(in));              string x = "";              string total = "";              x = r.readline();              int i=0;               while(x.length()>1)              {                  total=total+x.tostring().trim();                  i++;                  x = r.readline();              }              }             catch(exception e){              return e.tostring();             }            }          }).start();      return total;    } 

when call method returns null.

 rate_fetch rf=new rate_fetch();       string amt= rf.rate(prodlist); 

it want use thread only, try this

    public class rate_fetch {     string total = "";     boolean b = true;      public string rate(string dt) {         stringbuilder sb = new stringbuilder();         new thread(new runnable() {              public void run() {                  try {                      url url = new url(tally_ipaddr + "/prorate.jsp?plist="                             + sss.tostring().trim());                      httpurlconnection urlconnection = (httpurlconnection) url                             .openconnection();                     inputstream in = new bufferedinputstream(urlconnection                             .getinputstream());                     bufferedreader r = new bufferedreader(                             new inputstreamreader(in));                     stringbuilder sb = new stringbuilder();                     string s;                     while (true) {                         s = r.readline();                         if (s == null || s.length() == 0)                             break;                         sb.append(s);                     }                     b = true;                 } catch (exception e) {                     b = true;                 }             }          }).start();         while (b) {          }         total = sb.tostring();         return sb.tostring();      } }