Do you have Google App Engine enabled in your project preferences? GAE
doesn't allow you to connect to databases, and you usually get a
NoClassDefFoundError when you attempt to connect...
--Sri
On 10 May 2010 15:04, fomba collins <fomba_coll...@yahoo.com> wrote:
> Hi,
> I have a class (Connection) on the server side that accesses the
> database through hibernate. The connection on the server side is perfect. I
> want to use RPC to call these methods on the client side. I then create an
> Implementation class (ConnectionImpl) on the server that calls one of the
> methods of the Connection class.ie the method connecto. Here is the
> Implementation class.
>
> *
>
> public
> * *class* ConnectionImpl *extends* RemoteServiceServlet *implements*
>
> ConnectionService{
>
> /**
>
> *
>
> */
>
> *private* *static* *final* *long* *serialVersionUID* = 1L;
>
> Connection con = *new* Connection(); /*The class that performs database
> access through hibernate*/
>
> *public* *boolean* connecto(String login, String
> password)*throws*IllegalArgumentException{
>
> *return* con.connect(login, password);//connect() returns a boolean
>
> }
>
> }
>
> Then on the client side, I have the ConnectionService and
> ConnectionServiceAsync interfaces:
>
> public interface ConnectionService extends RemoteService {
> boolean connecto(String login, String password)throws
> IllegalArgumentException;
> }
>
> and
>
> *
>
> public
> * *interface* ConnectionServiceAsync {
>
> *void* connecto(String login, String password, AsyncCallback<Boolean>
> callback)
>
> *throws* IllegalArgumentException;
> }
>
> The web.xml conf file is as follows:
>
>
> <?
> xml version="1.0" encoding="UTF-8"?>
>
> <!
> DOCTYPE web-app
>
> PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
>
> "http://java.sun.com/dtd/web-app_2_3.dtd";>
>
> <
> web-app>
>
> <!-- Servlets -->
>
> <servlet>
>
> <servlet-name>connectionServlet</servlet-name>
>
> <servlet-class>com.server.ConnectionServiceImpl</servlet-class>
>
> </servlet>
>
> <servlet-mapping>
>
> <servlet-name>connectionServlet</servlet-name>
>
> <url-pattern>/webtop/connection</url-pattern>
>
> </servlet-mapping>
>
> <!-- Default page to serve -->
>
> <welcome-file-list>
>
> <welcome-file>Webtop.html</welcome-file>
>
> </welcome-file-list>
>
> </
> web-app>
>
>
>
> But when I run and enter values to execute through rpc, I get the following
> error:
>
>
>
>
>
> SEVERE: [1273482832366000] javax.servlet.ServletContext log: Exception
> while dispatching incoming RPC call
> *
>
> com.google.gwt.user.server.rpc.UnexpectedException
> *: Service method 'public abstract boolean
> com.extjs.gxt.samples.desktop.client.ConnectionService.connecto(java.lang.String,java.lang.String)
> throws java.lang.IllegalArgumentException' threw an unexpected exception:
> java.lang.NoClassDefFoundError: Could not initialize class
> com.extjs.gxt.samples.desktop.server.HibernateSessionFactory
>
> at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(
> *RPC.java:378*)
>
> at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(
> *RPC.java:581*)
>
> at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(
> *RemoteServiceServlet.java:188*)
>
> at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(
> *RemoteServiceServlet.java:224*)
>
> at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(
> *AbstractRemoteServiceServlet.java:62*)
>
> at javax.servlet.http.HttpServlet.service(
> *HttpServlet.java:713*)
>
> at javax.servlet.http.HttpServlet.service(
> *HttpServlet.java:806*)
>
> at org.mortbay.jetty.servlet.ServletHolder.handle(
> *ServletHolder.java:511*)
>
> at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(
> *ServletHandler.java:1166*)
>
> at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(
> *ServeBlobFilter.java:51*)
>
> at org.mortbay.jetty.servlet.ServletHandler$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 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.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(
> *DevAppEngineWebAppContext.java:70*)
>
> at org.mortbay.jetty.handler.HandlerWrapper.handle(
> *HandlerWrapper.java:152*)
>
> at
> com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(
> *JettyContainerService.java:349*)
>
> at org.mortbay.jetty.handler.HandlerWrapper.handle(
> *HandlerWrapper.java:152*)
>
> at org.mortbay.jetty.Server.handle(
> *Server.java:326*)
>
> at org.mortbay.jetty.HttpConnection.handleRequest(
> *HttpConnection.java:542*)
>
> at org.mortbay.jetty.HttpConnection$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.NoClassDefFoundError: Could not initialize class
> com.extjs.gxt.samples.desktop.server.HibernateSessionFactory
>
> at com.extjs.gxt.samples.desktop.server.BaseHibernateDAO.getSession(
> *BaseHibernateDAO.java:13*)
>
> at com.extjs.gxt.samples.desktop.server.EvutiDAO.findAll(
> *EvutiDAO.java:104*)
>
> at com.extjs.gxt.samples.desktop.server.Connection.getLogin(
> *Connection.java:42*)
>
> at com.extjs.gxt.samples.desktop.server.Connection.connect(
> *Connection.java:69*)
>
> at com.extjs.gxt.samples.desktop.server.ConnectionServiceImpl.connecto(
> *ConnectionServiceImpl.java:16*)
>
> 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.RPC.invokeAndEncodeResponse(
> *RPC.java:562*)
>
> ... 30 more
>
> Remote Procedure Call - Failure
>
>
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