If you write a servlet and add it to the servlet pipeline, your servlet’s service method is called for all requests that reach this stage in the pipeline. If your servlet does not call the passRequest() method (perhaps because an application exception is thrown), no content reaches the browser and the likely result is a Document Contains No Data message from the browser. Make sure your servlets are coded properly to avoid this problem.

Your servlet (whether it appears in the servlet pipeline or not) should generally not catch IOExceptions that occur when writing to the ServletOutputStream, as those exceptions indicate that the user has clicked the browser’s stop button. If you need to execute some code when the user clicks the stop button, your code should catch the IOException, do any needed processing, and then re-throw the IOException.