code: private boolean parseOverwriteHeader(HttpServletRequest req) {
  
          boolean overwrite = true;
          String overwriteHeader = req.getHeader(HEADER_OVERWRITE);
  
          if (overwriteHeader != null) {
              if (overwriteHeader.equalsIgnoreCase("T")) {
                  overwrite = true;
              } else {
                  overwrite = false;
              }
          }
  
          return overwrite;
      }
docs: Reads the information about overwriting out of the header of the
  request.<p>
  
  @param req the servlet request we are processing
  
  @return true if overwrite was set in the header otherwise false