Question

I configured GWT 2.4.0 + Hibernate 4.x

I used Using Data Transfer Objects (DTO) as integration strategy following the GWT tutorial:
https://developers.google.com/web-toolkit/articles/using_gwt_with_hibernate

But when I run the project as Web Application (using Google eclipse plugin), this exception is thrown:

Caused by: java.lang.NoClassDefFoundError: java.net.Socket is a restricted class. Please see the Google App Engine developer’s guide for more details.

The full exception:

Initial SessionFactory creation failed.java.lang.NoClassDefFoundError: java.net.Socket is a restricted class. Please see the Google  App Engine developer's guide for more details.
01/04/2012 22:11:39 com.google.appengine.tools.development.ApiProxyLocalImpl log
GRAVE: javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String web.reg.client.GreetingService.greetServer(java.lang.String) throws java.lang.IllegalArgumentException' threw an unexpected exception: java.lang.ExceptionInInitializerError
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:385)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:588)
    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:511)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:60)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:363)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.lang.ExceptionInInitializerError
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:17)
    at web.reg.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:36)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:104)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
    ... 34 more
Caused by: java.lang.NoClassDefFoundError: java.net.Socket is a restricted class. Please see the Google  App Engine developer's guide for more details.
    at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51)
    at org.hsqldb.HsqlSocketFactory.createSocket(Unknown Source)
    at org.hsqldb.HSQLClientConnection.openConnection(Unknown Source)
    at org.hsqldb.HSQLClientConnection.initConnection(Unknown Source)
    at org.hsqldb.HSQLClientConnection.<init>(Unknown Source)
    at org.hsqldb.jdbc.jdbcConnection.<init>(Unknown Source)
    at org.hsqldb.jdbcDriver.getConnection(Unknown Source)
    at org.hsqldb.jdbcDriver.connect(Unknown Source)
    at java.sql.DriverManager.getConnection(DriverManager.java:582)
    at java.sql.DriverManager.getConnection(DriverManager.java:154)
    at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:173)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcServicesImpl.java:242)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:117)
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71)
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2273)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2269)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1738)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778)
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:13)

I’ve read in this forum: http://www.mail-archive.com/[e-mail]/msg44312.html
that I should uncheck the “Use Google App Engine” Option on eclipse, and also remove the jars of this google app engine references.

Ok I did it.

But when I run the gwt via eclipse plugin, when I launch the application and send some data to be stored on server this exception is thrown:

Caused by: org.hibernate.HibernateException: Could not instantiate dialect class
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:82)
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:64)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:170)
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71)
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2273)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2269)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1738)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778)
    at web.reg.util.HibernateUtil.<clinit>(HibernateUtil.java:13)
    ... 28 more
Caused by: java.lang.ClassCastException: org.hibernate.dialect.HSQLDialect cannot be cast to org.hibernate.dialect.Dialect
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:73)

My hibernate.cfg.xml is realy using org.hibernate.dialect.HSQLDialect by the property:
org.hibernate.dialect.HSQLDialect

the .jar files I'm using are:

on GWT structure:


war/WEB-INF/lib:
|- antlr-2.7.7.jar
|- dom4j-1.6.1.jar
|- gwt-servlet.jar
|- hibernate-commons-annotations-4.0.1.Final.jar
|- hibernate-core-4.1.1.Final.jar
|- hibernate-entitymanager-4.1.1.Final.jar
|- hibernate-jpa-2.0-api-1.0.1.Final.jar
|- hsqldb.jar
|- javassist-3.15.0-GA.jar
|- jboss-logging-3.1.0.GA.jar
|- jboss-transaction-api_1.1_spec-1.0.0.Final.jar
|- jsr107cache-1.1.jar

What is missing? Or is there something I shouldn’t put?

Answer 1

This is a Jetty Classloader issue. I didn’t get this particular error myself, but the problem is detailed in this Hibernate Bug Report.

Vladimir Konkov’s suggestion to change the ClassLoaderServiceImpl.java to pass a null value to the constructor should work to resolve it.

this.classClassLoader = new ClassLoader(null) {
        @Override
        protected Class<?> findClass(String name) throws ClassNotFoundException {
            for ( ClassLoader loader : classLoadingClassLoaders ) {
                try {
                    return loader.loadClass( name );
                }
                catch (Exception ignore) {
                }
            }
            throw new ClassNotFoundException( "Could not load requested class : " + name );
        }
};