I'm facing the same issue and was suspecting a class loading issue. I thought I was inviting trouble when I would place the same Hibernate annotated class in both the server side code and the GWT client side, but until upgrading GWT 2.0 to GWT 2.4, I did not experience this ClassCastException problem.
As Alexander has experienced, things work fine when I deploy the .war to an external server, and only see problems running in the DevMode. I see different classes not being "cast-able" depending on my hibernate.cfg.xml. I'm still trying to sort out how the switch from GWT 2.0 to 2.4 is a factor because I made several changes, but I am glad to hear that I'm not the only one thinking this is a classloader issue. On Nov 18, 9:54 am, Thomas Broyer <t.bro...@gmail.com> wrote: > On Friday, November 18, 2011 2:21:33 PM UTC+1, Alexander Lochschmied wrote: > > > It only becomes: > > > Caused by: java.lang.ClassCastException: > > org.hibernate.dialect.MySQL5Dialect cannot be cast to > > org.hibernate.dialect.Dialect > > > We haven playing with those JARs as there may be incompatibilities (JPA 1 > > vs 2) I think. Currently we do *not *reference them > > (hibernate-jpa-2.0-api, hibernate-validator and validation-api). > > > Could it be a class loading issue? > > It's very likely the case yes; generally because the MySQL5Dialect comes > from the parent classloader of the one containing the Dialect class. Could > it be that some of your dependencies are not in the WEB-INF/lib? > > IMO, when using Maven, you should really make at least 2 projects: one for > the server and one for the client (you can possibly make server depend on > client, but I'd rather make a third project "shared" that both client and > server depend on); and you launch the server using the jetty-maven-plugin > or whatever, and then run the DevMode in -noserver mode for the client-side > code. > The problem is that there's no "scope=client" and "scope=server" in Maven, > so everything in scope=compile or scope=runtime will be copied to your > webapp's WEB-INF/lib, as expected, but will *also* be in the classpath of > the DevMode, because there's no way to know whether your client-side code > needs them or not; that leads to having all server classes twice on the > classpath of the webapp (because it's a child classloader of the DevMode's > one). -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
