I am trying to convert an object into JSON using the GSON library on Google App Engine. For some reason, it throws this exception and I don’t understand how to solve this. Any suggestions?
java.lang.SecurityException: java.lang.IllegalAccessException: Reflection is not allowed on private static final int java.util.BitSet.ADDRESS_BITS_PER_WORD
at com.google.appengine.runtime.Request.process-8d5b435d6736643f(Request.java)
at java.lang.reflect.AccessibleObject.setAccessible(AccessibleObject.java:29)
at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:141)
at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:123)
at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:148)
at com.google.gson.JsonSerializationVisitor.addAsArrayElement(JsonSerializationVisitor.java:139)
at com.google.gson.JsonSerializationVisitor.visitArray(JsonSerializationVisitor.java:83)
at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:109)
at com.google.gson.JsonSerializationVisitor.getJsonElementForChild(JsonSerializationVisitor.java:148)
at com.google.gson.JsonSerializationVisitor.addAsChildOfObject(JsonSerializationVisitor.java:126)
at com.google.gson.JsonSerializationVisitor.visitArrayField(JsonSerializationVisitor.java:95)
at com.google.gson.ObjectNavigator.navigateClassFields(ObjectNavigator.java:154)
at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:123)
at com.google.gson.JsonSerializationContextDefault.serialize(JsonSerializationContextDefault.java:56)
at com.google.gson.Gson.toJsonTree(Gson.java:230)
at com.google.gson.Gson.toJson(Gson.java:315)
at com.google.gson.Gson.toJson(Gson.java:270)
at com.google.gson.Gson.toJson(Gson.java:250)
at companionmodel.Sample_Model_PopulateServlet.printOutput(Sample_Model_PopulateServlet.java:59)
at companionmodel.Sample_Model_PopulateServlet.doGet(Sample_Model_PopulateServlet.java:28)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:693)
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$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:97)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
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 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.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:238)
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$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:135)
at com.google.apphosting.runtime.JavaRuntime.handleRequest(JavaRuntime.java:250)
at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:5838)
at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:5836)
at com.google.net.rpc.impl.BlockingApplicationHandler.handleRequest(BlockingApplicationHandler.java:24)
at com.google.net.rpc.impl.RpcUtil.runRpcInApplication(RpcUtil.java:398)
at com.google.net.rpc.impl.Server$2.run(Server.java:852)
at com.google.tracing.LocalTraceSpanRunnable.run(LocalTraceSpanRunnable.java:56)
at com.google.tracing.LocalTraceSpanBuilder.internalContinueSpan(LocalTraceSpanBuilder.java:576)
at com.google.net.rpc.impl.Server.startRpc(Server.java:807)
at com.google.net.rpc.impl.Server.processRequest(Server.java:369)
at com.google.net.rpc.impl.ServerConnection.messageReceived(ServerConnection.java:442)
at com.google.net.rpc.impl.RpcConnection.parseMessages(RpcConnection.java:319)
at com.google.net.rpc.impl.RpcConnection.dataReceived(RpcConnection.java:290)
at com.google.net.async.Connection.handleReadEvent(Connection.java:474)
at com.google.net.async.EventDispatcher.processNetworkEvents(EventDispatcher.java:831)
at com.google.net.async.EventDispatcher.internalLoop(EventDispatcher.java:207)
at com.google.net.async.EventDispatcher.loop(EventDispatcher.java:103)
at com.google.net.rpc.RpcService.runUntilServerShutdown(RpcService.java:251)
at com.google.apphosting.runtime.JavaRuntime$RpcRunnable.run(JavaRuntime.java:413)
at java.lang.Thread.run(Unknown Source)
Code I am using:
Gson gson = new Gson();
String json = gson.toJson(modelObject);
The app engine does support reflection – however you are trying to reflect on a private field of a JRE class:
…from http://code.google.com/appengine/docs/java/runtime.html#The_Sandbox:
I’d consider writing a custom serializer for Bitset.
See: http://sites.google.com/site/gson/gson-user-guide#TOC-Custom-Serialization-and-Deserializ
Also: http://groups.google.com/group/google-gson/browse_thread/thread/535892ffcf691aa/897f27e37e03ce58?lnk=gst&q=bitset#897f27e37e03ce58
http://groups.google.com/group/google-gson/browse_thread/thread/535892ffcf691aa