code: private byte[] encodeParameters(Map<String, String> params, String paramsEncoding) {
          StringBuilder encodedParams = new StringBuilder();
          try {
              for (Map.Entry<String, String> entry : params.entrySet()) {
                  encodedParams.append(URLEncoder.encode(entry.getKey(), paramsEncoding));
                  encodedParams.append('=');
                  encodedParams.append(URLEncoder.encode(entry.getValue(), paramsEncoding));
                  encodedParams.append('&');
              }
              return encodedParams.toString().getBytes(paramsEncoding);
          } catch (UnsupportedEncodingException uee) {
              throw new RuntimeException("Encoding not supported: " + paramsEncoding, uee);
          }
      }
docs: Converts <code>params</code> into an application/x-www-form-urlencoded encoded string.