access token - FitBit OAuth 2.0 Access_token resulting missing grant_type parameter value -

i implemented authorization step , got code value redirect_uri. , while implementing fitbit oauth accesstoken request (https://wiki.fitbit.com/display/api/oauth+2.0) getting following error:

warn : org.apache.http.impl.client.defaulthttpclient - authentication error: unable respond of these challenges: {oauth=www-authenticate: oauth realm="https%3a%2f%2fapi008-g4.prod.dal05.fitbit.com"} {"errors":[{"errortype":"oauth","fieldname":"n/a","message":"invalid_request, missing grant_type parameter value"}],"success":false} 

as per document supplied every recommended values , code like:

string authstring = fitbit.getclient_id()+":"+fitbit.getclient_secret(); string authencstring = base64.getencoder().encodetostring(authstring.getbytes()); url = fitbit.getaccesstoken_uri() + "?code="+code+"&grand_type="+fitbit.getgrant_type()+"&client_id="+fitbit.getclient_id()+         "&redirect_uri="+fitbit.getredirect_url(); string url3 = fitbit.getaccesstoken_uri();  httpclient httpclient = new defaulthttpclient(); httpget request = new httpget(url3); request.addheader("authorization", "basic " + authencstring); request.addheader("content-type","application/x-www-form-urlencoded"); request.addheader("code", code); request.addheader("grant_type",fitbit.getgrant_type()); request.addheader("client_id", fitbit.getclient_id()); request.addheader("redirect_uri", fitbit.getredirect_url());      httpresponse response = httpclient.execute(request);      string json = entityutils.tostring(response.getentity(), "utf-8"); 

here grant_type value authorization_code accesstoken_uri : https://api.fitbit.com/oauth2/token

can 1 solve this?

add grant_type=authorization_code body parameter instead of header parameter. can add client id , redirect_uri body parameter.