GWT serialization exception

Question

I have a simple service method which returns ArrayList. However when I call this method, I am getting an exception as follows:

com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: The response could not be deserialized
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:221)
    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: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.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: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:662)
Caused by: com.google.gwt.user.client.rpc.SerializationException: java.util.ArrayList/3821976829
    at com.google.gwt.user.client.rpc.impl.SerializerBase.getTypeHandler(SerializerBase.java:153)
    at com.google.gwt.user.client.rpc.impl.SerializerBase.instantiate(SerializerBase.java:114)
    at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:111)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter$ResponseReader$8.read(RequestCallbackAdapter.java:106)
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:214)
    ... 28 more

I am using Maven2, GWT 2.3 and JavaSE1.6

I know GWT can serialize ArrayList as I have used it countless times so I cant figure out what in world is going wrong over here.

See the exception occurs at: `RequestCallbackAdapter.java:221`. — jasop, Aug 17 '12 at 01:44

score 1 · Answer 1 · answered Jul 14 '11 at 01:06

1

Could you have forgotten to add the servlet and servlet-mapping entries in web.xml or the @RemoteServiceRelativePath annotation on your service interface?

answered Jul 14 '11 at 01:06

Josh

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score 0 · Answer 2 · answered Jul 12 '11 at 23:27

0

I'd start by making sure your Async, Service, and Impl classes match up to the RPC specification exactly. GWT will throw an error if you did anything (missing parameter, different return type) differently. Take a look at the google documentation on RPC, they sufficiently describe RPC calls (in a quite lengthy fashion).

answered Jul 12 '11 at 23:27

therin

1,448
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yeah have been checking that..nothing strikes out. – osome Jul 12 '11 at 23:34
you might want to try completely rebuilding your GWT app/project if you haven't already – therin Jul 12 '11 at 23:37
done. restarted eclipse, workstation...reimported project still no luck :( – osome Jul 12 '11 at 23:55

score 0 · Answer 3 · answered Jul 15 '11 at 12:02

The RPC interfaces and implementation do match, otherwise you would not be able to compile. I'm quite sure what you put in the ArrayList is causing the problem. Is it a generic ArrayList or a list of certain types? Try using Java Generic (e.g. ArrayList) to help the GWT compiler optimizing your code.

GWT serialization exception

3 Answers3