code: protected void fail(HttpServletRequest request, HttpServletResponse response, OAuthRequestFailedException failure) throws IOException, ServletException {
  		try {
  			//attempt to set the last exception.
  			request.getSession().setAttribute(OAUTH_FAILURE_KEY, failure);
  		}
  		catch (Exception e) {
  			//fall through....
  		}
  
  		if (LOG.isDebugEnabled()) {
  			LOG.debug(failure);
  		}
  
  		if (getOAuthFailureHandler() != null) {
  			getOAuthFailureHandler().handle(request, response, failure);
  		}
  		else {
  			throw failure;
  		}
  	}
docs: Common logic for OAuth failed. (Note that the default logic doesn't pass the failure through so as to not mess
  with the current authentication.)
  
  @param request  The request.
  @param response The response.
  @param failure  The failure.
  @throws ServletException in the case of an underlying Servlet API exception
  @throws IOException in the case of general IO exceptions