Dear all, after tons of tests maybe I have figured out what was the problem: I think that every exception that I have got can be caused by following elements:
1) I use .destroy() method but the best way is to use .markForDestroy() method; 2) I use .draw() methods for each element that is part of my main layout and then, at the end, I make a call on .show() method of the layout class: I have changed my code removing calls to .draw() subclasses and inserting a call of .draw() method of my main layout class (instead of using a call to .show() method); 3) I use always this. marker in order to identify variables belonging to my class but I have read that "this" marker could generate some problem if the JNSI function does not correctly map it so I have removed it. Thank you very much. Marco. On Monday, January 14, 2013 10:46:04 PM UTC+1, Marco wrote: > > Dear all, > I am having problems with a GWT program (it is not pure GWT but it makes > use of SmartGWT framework) developed using a MVP approach and I need your > support: I have created dedicated classes for each window that I want to > render; every time I want to switch between "pages" I call destroy method > to the "page" that I want to close (i.e. I call destroy method on Layout > object) and I launch a custom event in order to load the new "page". The > problem is that sometimes (I was not able to find a predefined pattern) the > method MyCurrentLoadedLayout.destroy(), called from my current loaded > layout, throws an exception and the program crash. > > This is the exception that has been launched: > > java.lang.ClassCastException: null > at java.lang.Class.cast(Class.java:2990) > at com.google.gwt.dev.shell.JsValueGlue.get(JsValueGlue.java:169) > at > com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:57) > at > com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172) > at > com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338) > at > com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219) > at > com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136) > at > com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571) > at > com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid(ModuleSpace.java:299) > at > com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid(JavaScriptHost.java:107) > at com.smartgwt.client.widgets.BaseWidget.destroy(BaseWidget.java) > at com.myTestClass.myTestLayout.destroyLytMain(myTestLayout.java:867) > [...] > > I am sure that the Layout class is not null because, as I wrote, the major > of the time the code works correctly. > This strange behavior happens, randomly, also when I try to launch an > event via EventBus: > > com.google.gwt.event.shared.UmbrellaException: Exception caught: null > at com.google.gwt.event.shared.EventBus.castFireEvent(EventBus.java:69) > at > com.google.gwt.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:57) > at com.myTestClass.myTestLayout$10.onSuccess(myTestLayout.java:842) > at > com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:232) > at > com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287) > at > com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) > at java.lang.reflect.Method.invoke(Method.java:597) > at > com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) > at > com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) > at > com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172) > at > com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338) > at > com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219) > at > com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136) > at > com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571) > at > com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279) > at > com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91) > at com.google.gwt.core.client.impl.Impl.apply(Impl.java) > at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:242) > at sun.reflect.GeneratedMethodAccessor139.invoke(Unknown Source) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) > at java.lang.reflect.Method.invoke(Method.java:597) > at > com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) > at > com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) > at > com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172) > at > com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:293) > at > com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:547) > at > com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364) > at java.lang.Thread.run(Thread.java:680) > > Please could you help me understanding which is the problem? What can I do > in order to figure out what is the cause? > Thank you vey much for your help and best Regards, > Marco. > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/qVf7Z9FRsKwJ. 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.
