GWT RCP - SerializationException - gwt

Question

Started a new project from scratch, converted to JPA, my persistence provider is EclipseLink, added the necessary libraries (eclipselink.jar, eclipselink.jar, javax.persistence, mysql-connector-java-5.1). Tested the connection, ping ok. Then created a new package New > JPA > Entities from Tables > Selected all Entities and Key generator > Identity.
GestorIpca.java
GestorIpcaService.util.getInstance().getLista(new AsyncCallback<ArrayList<Docente>>() {
#Override
public void onFailure(Throwable caught) {
Window.alert("Erro na Ligacao efectuada");
caught.getStackTrace();
}
#Override
public void onSuccess(ArrayList<Docente> result) {
Window.alert("Ligacao efectuada com sucesso:" + result.size());
}
});
GestorIpcaService
#RemoteServiceRelativePath("greet")
public interface GestorIpcaService extends RemoteService {
String greetServer(String name) throws IllegalArgumentException;
public static class util{
public static GestorIpcaServiceAsync instance;
public static GestorIpcaServiceAsync getInstance(){
if(instance == null){
instance = GWT.create(GestorIpcaService.class);
}
return instance;
}
}
public ArrayList<Docente> getLista() throws IllegalArgumentException;
}
GestorIpcaServiceAsync
public interface GestorIpcaServiceAsync {
void greetServer(String input, AsyncCallback<String> callback)
throws IllegalArgumentException;
void getLista(AsyncCallback<ArrayList<Docente>> callback);
}
GestorIpcaServiceImpl
#SuppressWarnings("serial")
public class GestorIpcaServiceImpl extends RemoteServiceServlet implements
GestorIpcaService {
public ArrayList<Docente> getLista() throws IllegalArgumentException {
//Criamos um EntityManager
EntityManager em = JpaUtil.getEntityManagerFactory().createEntityManager();
//Criamos a consulta
String consulta = "SELECT r from Docente r";
//Executamos a consulta
Query q = em.createQuery(consulta);
ArrayList<Docente> lista = new ArrayList<Docente>(q.getResultList());
return lista;
}
/* public static void main(String args[]){
GestorIpcaServiceImpl serviceImpl = new GestorIpcaServiceImpl();
for (Docente docente : serviceImpl.getLista()){
System.out.println("nome: " + docente.getNome());
}
}
*/
In this file i tried to run as > Java Application and in Console showed me 2 records.
Package com.GestorIpca.factory
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
public class JpaUtil {
private static final EntityManagerFactory emf;
//Método estático
static{
//BLoco try
try
{
//Criação de EntityManagerFactory
emf = Persistence.createEntityManagerFactory("GestorIpca");
}catch (Throwable e){
//Controlar as excepções
System.err.println("A criação de SessionFactory falhou" + e);
e.printStackTrace();
throw new ExceptionInInitializerError(e);
}
}
public static EntityManagerFactory getEntityManagerFactory(){
return emf;
}
}
My persistence.xml was created automatically. Placed inside META-INF
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="GestorIpca">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>com.GestorIpca.shared.Ano</class>
<class>com.GestorIpca.shared.Categoria</class>
<class>com.GestorIpca.shared.Curso</class>
<class>com.GestorIpca.shared.Disciplina</class>
<class>com.GestorIpca.shared.Disponibilidade</class>
<class>com.GestorIpca.shared.Docente</class>
<class>com.GestorIpca.shared.Sala</class>
<class>com.GestorIpca.shared.Semestre</class>
<class>com.GestorIpca.shared.TipoCurso</class>
<class>com.GestorIpca.shared.Turma</class>
<class>com.GestorIpca.shared.User</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/timetable"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="k771u3"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties>
</persistence-unit>
</persistence>
Last step > Run as > Web Application
Error > Could not connect to database and print a stack trace in Eclipse Console
[EL Info]: 2011-05-09 10:03:08.78--ServerSession(8068087)--EclipseLink, version: Eclipse Persistence Services - 2.2.0.v20110202-r8913
[EL Info]: 2011-05-09 10:03:09.297--ServerSession(8068087)--file:/C:/Users/Martinho/WorkSpace/GestorIpca/war/WEB-INF/classes/_GestorIpca login successful
Starting Jetty on port 8888
[WARN] Exception while dispatching incoming RPC call
com.google.gwt.user.client.rpc.SerializationException: java.lang.reflect.InvocationTargetException
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeWithCustomSerializer(ServerSerializationStreamWriter.java:764)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:727)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:616)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:152)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:534)
at com.google.gwt.user.server.rpc.RPC.encodeResponse(RPC.java:616)
at com.google.gwt.user.server.rpc.RPC.encodeResponseForSuccess(RPC.java:474)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:571)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeWithCustomSerializer(ServerSerializationStreamWriter.java:746)
... 30 more
Caused by: com.google.gwt.user.client.rpc.SerializationException: Type 'org.eclipse.persistence.indirection.IndirectSet' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.: instance = {IndirectSet: not instantiated}
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:614)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:152)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:534)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeClass(ServerSerializationStreamWriter.java:704)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:734)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:616)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:152)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:534)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeClass(ServerSerializationStreamWriter.java:704)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:734)
at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:616)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
at com.google.gwt.user.client.rpc.core.java.util.Collection_CustomFieldSerializerBase.serialize(Collection_CustomFieldSerializerBase.java:45)
at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serialize(ArrayList_CustomFieldSerializer.java:38)
... 35 more
[ERROR] 500 - POST /gestoripca/greet (127.0.0.1) 57 bytes
Request headers
Host: 127.0.0.1:8888
Connection: keep-alive
Referer: http://127.0.0.1:8888/GestorIpca.html?gwt.codesvr=127.0.0.1:9997
Content-Length: 132
Origin: http://127.0.0.1:8888
X-GWT-Module-Base: http://127.0.0.1:8888/gestoripca/
X-GWT-Permutation: HostedMode
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.30 Safari/534.30
Content-Type: text/x-gwt-rpc; charset=UTF-8
Accept: */*
Accept-Encoding: gzip,deflate,sdch
Accept-Language: pt-PT,pt;q=0.8,en-US;q=0.6,en;q=0.4
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Response headers
Content-Type: text/plain
Note: I changed in package com.GestorIpca.shared all my classes generated from tables
public class Ano implements Serializable
to
public class Ano implements IsSerializable
changed also my GestorIpca.gwt.xml and added this lines in end
<extend-configuration-property name="rpc.blacklist" value="com.google.gwt.user.client.ui.*Collection"/>
<extend-configuration-property name="rpc.blacklist" value="-.*List"/>
<extend-configuration-property name="rpc.blacklist" value="-.*Map"/>
<extend-configuration-property name="rpc.blacklist" value="-.*Collection"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.HashMap"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.LinkedHashMap"/>
<extend-configuration-property name="rpc.blacklist" value="+java.util.ArrayList"/>
What am i missing?

Answer 1

I depends on how your entities were defined. Maybe there are connections that GWT RPC doesn´t like. in this case i´d suggest create DTO´s or implement RequestFactory

Answer 2

Without knowing what your entities look like I would guess from the exception that the reason is probably how your entities get enhanced by your persistence provider:
What this means for GWT RPC is that by the time the object is ready to be transferred over the wire, it actually isn't the same object that the compiler thought was going to be transferred, so when trying to deserialize, the GWT RPC mechanism no longer knows what the type is and refuses to deserialize it.
Cited from: http://code.google.com/intl/de-DE/webtoolkit/articles/using_gwt_with_hibernate.html
That article also suggests how to create DTOs to solve this problem.

Answer 3

I know this is a very old question, but I ran into this exact issue tonight.
GWT Serialization doesn't seem to like java.util.Set. I almost feel like it was confusing java.util.Set with org.eclipse.persistence.indirection.IndirectSet.
Once I switched Set to ArrayList, the error went away.