gwt+hibernate集成的时候出现access denied（拒绝访问）异常

     at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
     at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
     at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
     at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
     at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
     at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
     at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.lang.ExceptionInInitializerError
     at com.topsoft.gwt.server.HibernateUtil.<clinit>(HibernateUtil.java:17)
     at com.topsoft.gwt.server.HellowordServiceImpl.helloUser(HellowordServiceImpl.java:48)
     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.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100)
     at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562)
     ... 30 more
Caused by: java.security.AccessControlException: access denied (java.lang.RuntimePermission accessClassInPackage.sun.io)
     at java.security.AccessControlContext.checkPermission(Unknown Source)
     at java.security.AccessController.checkPermission(Unknown Source)
     at java.lang.SecurityManager.checkPermission(Unknown Source)
     at com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166)
     at java.lang.SecurityManager.checkPackageAccess(Unknown Source)
     at java.lang.ClassLoader$1.run(Unknown Source)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.lang.ClassLoader.checkPackageAccess(Unknown Source)
     at com.ibm.db2.jcc.b.a.<init>(a.java:238)
     at com.ibm.db2.jcc.b.b.a(b.java:1624)
     at com.ibm.db2.jcc.c.p.a(p.java:350)
     at com.ibm.db2.jcc.c.p.<init>(p.java:404)
     at com.ibm.db2.jcc.b.b.<init>(b.java:256)
     at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:163)
     at java.sql.DriverManager.getConnection(Unknown Source)
     at java.sql.DriverManager.getConnection(Unknown Source)
     at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:110)
     at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:73)
     at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1928)
     at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1211)
     at com.topsoft.gwt.server.HibernateUtil.<clinit>(HibernateUtil.java:12)
     ... 37 more

该异常是在
sessionFactory = new Configuration().configure().buildSessionFactory();   
时发生的，但是我用test程序能够正确访问到数据库啊
是gwt和hibernate发生冲突？
求教高手帮忙！

项目 右键 --> google--> app engine setting--> use google app engine 勾去了

GWT 与HIBERNATE 兼容不是太好 最好用JDO

让我挤死在前排