i m using GWT & hibernate and i try to send mail and geeting this error

com.google.apphosting.api.ApiProxy$CallNotFoundException: The API package 'mail' or call 'Send()' was not found.
at com.google.apphosting.api.ApiProxy.makeSyncCall(ApiProxy.java:98)
at com.google.apphosting.api.ApiProxy.makeSyncCall(ApiProxy.java:50)
at com.google.appengine.api.mail.MailServiceImpl.doSend(MailServiceImpl.java:95)
at com.google.appengine.api.mail.MailServiceImpl.send(MailServiceImpl.java:32)
at com.google.appengine.api.mail.stdimpl.GMTransport.sendMessage(GMTransport.java:247)
at javax.mail.Transport.send0(Transport.java:151)
at javax.mail.Transport.send(Transport.java:80)
at com.vopenidauth.server.VoiceAuth.sendMail1(VoiceAuth.java:986)
at com.vopenidauth.server.LoginServiceImpl.sendMail(LoginServiceImpl.java:1676)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
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)

This isssue is sloved

i have used mailapi jar files working fine now anyway this error not for hibernate sorry to put here

initially i thought because of hibernate its not working fine but now its work fine