code: public String put(File file) throws IOException {
  
          if (!connection.isOpen())
              connection.open();
  
          connection.prepare("PUT");
  
          String contentType = connection.getHeader("Content-Type");
          if (contentType == null)
              contentType = connection.getHeader("content-type");
          if (contentType == null || contentType.isEmpty()) {
              /**
               * Default it to application/octet-stream if nothing has been specified
               */
              connection.setHeader("Content-Type", "application/octet-stream");
          }
  
          OutputStream outStream = connection.getOutputStream();
          InputStream inStream = new FileInputStream(file);
  
          byte[] buf = new byte[1024];
          int len = 0;
          while (len != -1)
          {
            len = inStream.read(buf);
            if (len > 0)
              outStream.write(buf, 0, len);
          }
  
          inStream.close();
          outStream.close();
  
          BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getConnection().getInputStream()));
          StringBuffer responseBuffer = new StringBuffer();
          String line = null;
          while ((line = reader.readLine()) != null) {
              responseBuffer.append(line).append('\n');
          }
  
          reader.close();
  
          connection.getConnection().disconnect();
  
          response = new HttpResponse(responseBuffer.toString().getBytes());
          response.setCode(connection.getConnection().getResponseCode());
          if (response.getCode() < 200 || response.getCode() >= 300)
          {
              response.setMessage(connection.getConnection().getResponseMessage());
              throw new IOException("Error uploading file: " + response.getCode() + " -- " + response.getMessage());
          }
  
          return getResponse();
      }
docs: Upload a text file to the destination URL
  @param file the file to be uploaded
  @param force whether to overwrite if the destination file is newer
  @return string with the response from the server