Hi Andrey, Andrey Rahimov wrote:
> Hello! > > I found very weird and annoying behavior in xstream(1.4.7 and tried 1.4.5) > library on Android. > > Basically ClassCastException if not recreate XStream object whenever > deserialize new type of annotated object. > > More details here: > http://stackoverflow.com/questions/26778983/xstream-classcastexception-if-not-recreate-xstream-object-whenever-deserialize-n > > Is here any possibility to avoid recreating xStream object every time? There's normally no need to create a new instance every time. Normally, you simply create the instance, set it up and use it then everywhere (even concurrently). However, setting up the XStream is *not* thread-safe, i.e. if you use auto- detection for annotations or call processAnnotations, you will better use an own instance for each thread. See also FAQ, Javadoc and the annotations tutorial: - http://xstream.codehaus.org/faq.html#Scalability_Thread_safety - http://xstream.codehaus.org/javadoc/com/thoughtworks/xstream/XStream.html#autodetectAnnotations(boolean) - http://xstream.codehaus.org/annotations-tutorial.html#AutoDetect > Also even recreating xStream I'm getting this error approx. 4 crashes on > 3000 users. You can get in trouble if you marshal/unmarshal system resources: - http://xstream.codehaus.org/faq.html#Serialization_types > Can be the problem in our model? You call processAnnotations on-the-fly i.e. you change the setup of the XStream instance. Every XStream instance builds internal caches during the (un)marshalling process and - apart from the concurrency problem - you might get surprising results, e.g. if an alias has been defined twice or a converter instance is already used for a type, you can register something different as long as you want, it won't have any effect. However, since you're creating a new XStream instance yourself, you should not be affected. But you realize that your code is not thread-safe also? You create a new XStream instance and keep it in a member. Then you use that member in processAnnotations again and later on in fromBody. If fromBoby is called concurrently, you actually have no clue about which XStream instance is used in which state at which time ... and your code silently assumes that every type you have handled with toBody will use an XStream instance that has marshalled the same type in fromBody already before in the same run. BTW: Your processAnnotations method with the loop is superfluous, XStream did the same already. > > Regards, Andrey Rahimov Cheers, Jörg --------------------------------------------------------------------- To unsubscribe from this list, please visit: http://xircles.codehaus.org/manage_email
