Thanks a lot, it was very helpful!
G�bor
----- Original Message -----
From: Kevin Mukhar <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 28, 2000 4:56 PM
Subject: Re: ServletException and more
> Suhai G�bor wrote:
> >
> > Hi everyone!
> >
> > 1. Am I thinking right that when I throw a ServletException in the
doPost or
> > doGet method, it only affects the current request, and not all? I mean,
> > other requests can come in and can be handled independently.
>
> Yes. An exception only affects the current thread; other request threads
> are unaffected.
>
> > What if I throw
> > this exception in the init method? Does my servlet load into the memory
and
> > can it handle requests?
>
> No. If you throw an exception in the init() method, the servlet
> container will not allow requests to be sent to the servlet because the
> servlet did not successfully complete the init().
>
> From the Servlet 2.3 Specification:
>
> "2.3.2.1 Error Conditions on Initialization
> "During initialization, the servlet instance can signal that it is not
> to be placed into active service by throwing an UnavailableException or
> ServletException.If a servlet instance throws an exception of this type,
> it must not be placed into active service and the instance must be
> immediately released by the servlet container. The destroy method is not
> called in this case as initialization was not considered to be
> successful."
>
> > 2. In my servlet I use some helper class, which can throw exceptions.
> >
> > doPost() throws ServletException {
> > try {
> > handleRequest();
> > }
> > catch (HandleException he) {
> > throw new ServletException();
> > }
> > }
> >
> > handleRequest() throws HandleException {
> > try {
> > getSomethingFromDB();
> > }
> > catch (DBException dbe) {
> > throw new HandleException();
> > }
> > }
> >
> > getSomethingFromDB throws DBException
> >
> > Is it a good practice or I have to forget it and do something else
(throw
> > RuntimeException in getSomethingFromDB)?
>
> No. I do not consider the above to be good practice. Look at what
> happens when an exception is thrown. The exception gets thrown up the
> stack until it reaches doPost, which throws the ServletException. The
> servlet container catches this exception, so on the server-side there is
> no problem. The servlet container does not send a response back when it
> catches an exception. On the client side however, the client waits and
> waits and never gets a response from the server, until it finally times
> out.
>
> In my opinion, your servlet should always send a response back to the
> client. You can still throw the exception up to the servlet container if
> you want, but you should also send a response back to the client which
> says that the request could not be processed.
>
> K Mukhar
>
>
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