code: private byte[] readFile(String uriWithParams) {
  
          try {
              String pathAndQuery = OpenCms.getLinkManager().getRootPath(m_cms, uriWithParams);
              URI uri = new URI(pathAndQuery);
              String path = uri.getPath();
              CmsFile file = m_rootCms.readFile(path);
              return file.getContents();
          } catch (Exception e) {
              LOG.error("Problem with reading CSS " + uriWithParams + ": " + e.getLocalizedMessage(), e);
              return null;
          }
      }
docs: Reads a file from the VFS.<p>
  
  @param uriWithParams the
  @return the file data