when i invoking a rpc service with a onclick() method, I encounter a Exception:
Mar 12, 2010 11:45:40 AM com.google.appengine.tools.development.ApiProxyLocalImpl log SEVERE: [1268394340650000] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract tk.jo32.s.client.UrlInfoWrapper tk.jo32.s.client.UrlService.getUrlInformation(java.lang.String)' threw an unexpected exception: java.lang.NullPointerException 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: 487) at org.mortbay.jetty.servlet.ServletHandler $CachedChain.doFilter(ServletHandler.java:1093) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java: 51) at org.mortbay.jetty.servlet.ServletHandler $CachedChain.doFilter(ServletHandler.java:1084) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java: 43) at org.mortbay.jetty.servlet.ServletHandler $CachedChain.doFilter(ServletHandler.java:1084) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java: 121) at org.mortbay.jetty.servlet.ServletHandler $CachedChain.doFilter(ServletHandler.java:1084) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java: 360) 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: 712) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java: 405) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java: 70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java: 139) at com.google.appengine.tools.development.JettyContainerService $ApiProxyHandler.handle(JettyContainerService.java:352) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java: 139) at org.mortbay.jetty.Server.handle(Server.java:313) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java: 506) at org.mortbay.jetty.HttpConnection $RequestHandler.content(HttpConnection.java:844) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java: 396) at org.mortbay.thread.BoundedThreadPool $PoolThread.run(BoundedThreadPool.java:442) Caused by: java.lang.NullPointerException at tk.jo32.s.server.UrlServiceImpl.getUrlInformation(UrlServiceImpl.java: 20) 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: 100) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java: 562) ... 30 more What is strange is that when i do it the second time, everything goes right.without this exception of course... I've been puzzled with this problem for a long time, is any one can help me? -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.