code: private void saveNestedVariables() {
  	if (nestedVars != null) {
  	    Iterator iter = nestedVars.iterator();
  	    while (iter.hasNext()) {
  		String varName = (String) iter.next();
  		varName = findAlias(varName);
  		Object obj = invokingJspCtxt.getAttribute(varName);
  		if (obj != null) {
  		    originalNestedVars.put(varName, obj);
  		}
  	    }
  	}
      }
docs: Saves the values of any NESTED variables that are present in
  the invoking JSP context, so they can later be restored.