Hi, I don't understand why you've used "transient". Can you explain? Sorry, "mutable servlet field" was not the error. It was "A non- serializable value is stored into a non-transient field of a serializable class". My mistake. This is why I added the transient field thinking it would fix the problem. It did fix the problem but I wasn't sure if that is the correct thing to do.

Hi, ok that's better indeed. The reason is that according to the spec a I was hoping upon de serialization it will call init() where i initialize these variables. But I can't find a reference that says so (yet). One instance variable used is provided by jackrabbit library which is not serializable. I can do a custom serialization or, I can create these instance variable for each request (get***) which is a waste. Looking around to see if there is another way. Thanks. - Asiri _______________________________________________ devs mailing list devs(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/devs

Hi Vincent, On Tue, Oct 20, 2009 at 6:18 PM, Vincent Massol &lt;vincent(a)massol.net&gt; wrote: jackrabbit DavServlet has following abstract methods: <code> /** * Checks if the precondition for this request and resource is valid. * * @param request * @param resource * @return */ abstract protected boolean isPreconditionValid(WebdavRequest request, DavResource resource); /** * Returns the <code>DavSessionProvider</code>. * * @return the session provider */ abstract public DavSessionProvider getDavSessionProvider(); /** * Returns the <code>DavSessionProvider</code>. * * @param davSessionProvider */ abstract public void setDavSessionProvider(DavSessionProvider davSessionProvider); /** * Returns the <code>DavLocatorFactory</code>. * * @return the locator factory */ abstract public DavLocatorFactory getLocatorFactory(); /** * Sets the <code>DavLocatorFactory</code>. * * @param locatorFactory */ abstract public void setLocatorFactory(DavLocatorFactory locatorFactory); /** * Returns the <code>DavResourceFactory</code>. * * @return the resource factory */ abstract public DavResourceFactory getResourceFactory(); /** * Sets the <code>DavResourceFactory</code>. * * @param resourceFactory */ abstract public void setResourceFactory(DavResourceFactory resourceFactory); /** * Returns the value of the 'WWW-Authenticate' header, that is returned in * case of 401 error. * * @return value of the 'WWW-Authenticate' header */ abstract public String getAuthenticateHeaderValue(); </code> Now I have few doubts about why there are setXXX() methods but the point is we need those instance variables if we are to implement these methods.

Thanks. - Asiri > The CM would be retrieved from the servlet context. > > Thanks > -Vincent > > On Oct 20, 2009, at 2:36 PM, Asiri Rathnayake wrote: > >> Hi, >> >> >> ok that's better indeed. The reason is that according to the spec a >>> Servlet can be serialized (saved on disk) if the memory becomes low >>> and thus must be able to be loaded back into memory at a later >>> point >>> (the same need for load-balancing). >>> >>> However your change has introduced another problem: transient means >>> the field will not be saved when the servlet is serialized. Thus >>> when >>> it's deserialized these fields will be null and the code will >>> fail... >>> >>> Whereas before the servlet would have failed on serialization, >>> it'll >>> now fail on deserialization... >>> >>> Note: Deserialization will not call the constructor. >>> >> >> I was hoping upon de serialization it will call init() where i >> initialize >> these variables. But I can't find a reference that says so (yet). >> >> >> >>> Solution: either make the field objects serializable or capture >>> deserialization to set up the transient field values. Note that >>> this >>> last solution may potentially cause problems with threading so this >>> might need to be synchronized I think. The best solution is to make >>> the field Objects Serializable IMO. >>> >> >> One instance variable used is provided by jackrabbit library which >> is not >> serializable. I can do a custom serialization or, >> >> I can create these instance variable for each request (get***) which >> is a >> waste. >> >> Looking around to see if there is another way. >> >> Thanks. >> >> - Asiri >> >> >>> >>> WDYT? >>> >>> Thanks >>> -Vincent

On 10/20/2009 02:16 PM, Asiri Rathnayake wrote: Why don't you make them static? Instance members of a singleton class is roughly equivalent to static members.