Serialization Exception

[richip]

We're coming up with a SerializationException for an RPC call DTO that
we can't seem to resolve. Essentially, I've added an instance of a
class that extends ArrayList<VStruct> (where VStruct is a Serializable
class) and contains one Serializable field. Does someone know what our
problem might be? If not, are there tips on how to debug /.
troubleshoot these SerializationException problems?

[Jens]

Do you have a no-arg default constructor in your class?

[richip]

Not originally, but I added it (not the first time I got bit by this)
and it's still giving me a SerializationException:

com.google.gwt.user.client.rpc.SerializationException
at
com.google.gwt.user.client.rpc.impl.SerializerBase.getTypeHandler(SerializerBase.java:
153)
at
com.google.gwt.user.client.rpc.impl.SerializerBase.serialize(SerializerBase.java:
125)
at
com.google.gwt.user.client.rpc.impl.ClientSerializationStreamWriter.serialize(ClientSerializationStreamWriter.java:
179)
at
com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:
126)
at
com.google.gwt.user.client.rpc.core.java.util.Map_CustomFieldSerializerBase.serialize(Map_CustomFieldSerializerBase.java:
52)
at
com.google.gwt.user.client.rpc.core.java.util.HashMap_CustomFieldSerializer.serialize(HashMap_CustomFieldSerializer.java:
40)
at
com.google.gwt.user.client.rpc.core.java.util.HashMap_FieldSerializer.serial(HashMap_FieldSerializer.java:
23)
at
com.google.gwt.user.client.rpc.impl.SerializerBase.serialize(SerializerBase.java:
126)
at
com.google.gwt.user.client.rpc.impl.ClientSerializationStreamWriter.serialize(ClientSerializationStreamWriter.java:
179)
at
com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:
126)
at
com.enabil.vega.gwt.shared.VStruct_FieldSerializer.serialize(VStruct_FieldSerializer.java:
20)
at
com.enabil.vega.gwt.shared.VStruct_FieldSerializer.serial(VStruct_FieldSerializer.java:
33)
at
com.google.gwt.user.client.rpc.impl.SerializerBase.serialize(SerializerBase.java:
126)
at
com.google.gwt.user.client.rpc.impl.ClientSerializationStreamWriter.serialize(ClientSerializationStreamWriter.java:
179)
at
com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:
126)
at
com.google.gwt.user.client.rpc.core.java.util.Map_CustomFieldSerializerBase.serialize(Map_CustomFieldSerializerBase.java:
52)
at
com.google.gwt.user.client.rpc.core.java.util.HashMap_CustomFieldSerializer.serialize(HashMap_CustomFieldSerializer.java:
40)
at
com.google.gwt.user.client.rpc.core.java.util.HashMap_FieldSerializer.serial(HashMap_FieldSerializer.java:
23)
at
com.google.gwt.user.client.rpc.impl.SerializerBase.serialize(SerializerBase.java:
126)
at
com.google.gwt.user.client.rpc.impl.ClientSerializationStreamWriter.serialize(ClientSerializationStreamWriter.java:
179)
at
com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:
126)
at
com.enabil.vega.gwt.shared.VStruct_FieldSerializer.serialize(VStruct_FieldSerializer.java:
20)
at
com.enabil.vega.gwt.shared.VStruct_FieldSerializer.serial(VStruct_FieldSerializer.java:
33)
at
com.google.gwt.user.client.rpc.impl.SerializerBase.serialize(SerializerBase.java:
126)
at
com.google.gwt.user.client.rpc.impl.ClientSerializationStreamWriter.serialize(ClientSerializationStreamWriter.java:
179)
at
com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:
126)
at
com.enabil.vega.gwt.client.VegaService_Proxy.createShellAccount(VegaService_Proxy.java:
61)
at
com.enabil.vega.gwt.client.task.accountcreation.core.AccountCreationCreateShellAccountController.handleAppTaskFinished(AccountCreationCreateShellAccountController.java:
67)
at
com.enabil.vega.gwt.client.task.navwizard.core.VegaNavigationWizard.onNavFinishedEvent(VegaNavigationWizard.java:
342)
at
com.enabil.vega.gwt.client.task.navwizard.core.VegaNavEvent.dispatch(VegaNavEvent.java:
32)
at
com.enabil.vega.gwt.client.task.navwizard.core.VegaNavEvent.dispatch(VegaNavEvent.java:
1)
at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
at
com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:
193)
at
com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:
88)
at
com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:
127)
at
com.enabil.vega.gwt.client.task.navwizard.core.VegaNavigationWizard
$2.onClick(VegaNavigationWizard.java:236)
at
com.smartgwt.client.widgets.events.ClickEvent.dispatch(ClickEvent.java:
98)
at
com.smartgwt.client.widgets.events.ClickEvent.dispatch(ClickEvent.java:
1)
at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
at
com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:
193)
at
com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:
88)
at
com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:
127)
at
com.smartgwt.client.widgets.BaseWidget.fireEvent(BaseWidget.java:66)
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:592)
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:
167)
at
com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:
326)
at
com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:
207)
at
com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:
132)
at
com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:
561)
at
com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:
269)
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:214)
at sun.reflect.GeneratedMethodAccessor87.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
25)
at java.lang.reflect.Method.invoke(Method.java:592)
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:
167)
at
com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:
281)
at
com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:
531)
at
com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:
352)
at java.lang.Thread.run(Thread.java:595)

[cri]

Just a wild guess. Is this problem happening in Chrome? If so,
completely clear your browser cache and retry.

[richip]

I've figured it out, but am not sure how to fix it. The List that I'm
using uses a class that has a field that uses generic types. In the
above case, VStruct has one field (fieldType) that's of type
FieldType<T>. So I'm guessing it has nothing to do with Lists but
rather that one type. So what's the rule with generics? Should I use a
field of type FieldType<T extends Serializable>?

> > com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChanne lServer.java:
> > 281)
> >     at
> > com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChan nelServer.java:

[iPeel]

I've had so many of these which are nothing to do with serialization
errors themselves, but references to null objects or null objects
within the object class.