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Persist list of Entities with <int-jpa:outbound-channel-adapter

I may be missing something here but I cannot seem to find any docs about persisting a List of Entities using Spring Integration JPA Outbound Channel Adapter. I have an extremely simple scenario that should poll a database and copy new data across to another database. Thus:
<int-jpa:inbound-channel-adapter channel="myChannel"
entity-class="my.package.MyClass"
entity-manager="mysqlEntityManager"
auto-startup="true">
<int:poller fixed-rate="5000">
<int:transactional propagation="REQUIRED" transaction-manager="mysqlTransactionManager"/>
</int:poller>
</int-jpa:inbound-channel-adapter>
<int:channel id="myChannel" />
<int-jpa:outbound-channel-adapter channel="myChannel"
entity-class="my.package.MyClass"
entity-manager="hsqldbEntityManager">
<int-jpa:transactional transaction-manager="hsqldbTransactionManager" />
</int-jpa:outbound-channel-adapter>
The inbound-channel-adapter returns a List<MyClass> and then the outbound-channel-adapter throws the stack trace below...
How do I configure the adapter to accept a list of entites? I do not want to set max messages per poll in the inbound adapter/poller, as I would prefer minimal database operations.
Any help appreciated.
Spring docs:
http://static.springsource.org/spring-integration/docs/3.0.0.M1/reference/html/jpa.html
[task-scheduler-1] ERROR org.springframework.integration.handler.LoggingHandler - org.springframework.integration.MessageHandlingException: error occurred in message handler [org.springframework.integration.jpa.outbound.JpaOutboundGateway#165d2be]
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:79)
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 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy24.handleMessage(Unknown Source)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:102)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:77)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:157)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:128)
at org.springframework.integration.core.MessagingTemplate.doSend(MessagingTemplate.java:288)
at org.springframework.integration.core.MessagingTemplate.send(MessagingTemplate.java:149)
at org.springframework.integration.endpoint.SourcePollingChannelAdapter.handleMessage(SourcePollingChannelAdapter.java:97)
at org.springframework.integration.endpoint.AbstractTransactionSynchronizingPollingEndpoint.doPoll(AbstractTransactionSynchronizingPollingEndpoint.java:82)
at org.springframework.integration.endpoint.AbstractPollingEndpoint$1.call(AbstractPollingEndpoint.java:146)
at org.springframework.integration.endpoint.AbstractPollingEndpoint$1.call(AbstractPollingEndpoint.java:144)
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 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy23.call(Unknown Source)
at org.springframework.integration.endpoint.AbstractPollingEndpoint$Poller$1.run(AbstractPollingEndpoint.java:236)
at org.springframework.integration.util.ErrorHandlingTaskExecutor$1.run(ErrorHandlingTaskExecutor.java:52)
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:48)
at org.springframework.integration.util.ErrorHandlingTaskExecutor.execute(ErrorHandlingTaskExecutor.java:49)
at org.springframework.integration.endpoint.AbstractPollingEndpoint$Poller.run(AbstractPollingEndpoint.java:231)
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:53)
at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:81)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Unknown entity: java.util.ArrayList
at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:692)
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 org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
at $Proxy18.merge(Unknown Source)
at org.springframework.integration.jpa.core.DefaultJpaOperations.merge(DefaultJpaOperations.java:175)
at org.springframework.integration.jpa.core.JpaExecutor.executeOutboundJpaOperation(JpaExecutor.java:223)
at org.springframework.integration.jpa.outbound.JpaOutboundGateway.handleRequestMessage(JpaOutboundGateway.java:81)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:134)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:73)
... 48 more
Caused by: org.hibernate.MappingException: Unknown entity: java.util.ArrayList
at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:693)
at org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1485)
at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:232)
at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:84)
at org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:867)
at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:851)
at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:855)
at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:686)
... 59 more

I have created a Jira in order to make that improvement:
https://jira.springsource.org/browse/INT-3029
As a work-around you could also extend DefaultJpaOperations (org.springframework.integration.jpa.core) and customize the persist() method, allowing you to handle a Collection type parameters. For some details see:
Batch inserts with JPA/EJB3
The adapters have an XML namespace attribute jpa-operations, allowing you to provide a reference to custom implementations. For more details, please see http://static.springsource.org/spring-integration/docs/latest-ga/reference/html/jpa.html#jpa-namespace-support-common-attributes

The outbound JPA adapter doesn't currently support persisting a list of entities; feel free to open a new JIRA Issue. You can add a simple <splitter/> before the outbound adapter (no attributes, just input and output channels) and it will bust the list into individual entitities.
However, with your current configuration, each persist will be done in a separate transaction.
Regardless, you probably want to synchronize the two transactions anyway so you should really start the hsql transaction at the same time as the mysql transaction so that Spring will make best efforts to synchronize the two transactions (commit them as close together as possible).
To do that, you'd need something like the ChainedTransactionManager in the 'Best Efforts 1PC' section of Dave Syer's excellent article on this subject.
This way, each of the split entities will be committed in the same transaction.

issue with writing to KML file using JavaAPIForKML

I was trying to generate KML file from a text file.
When I am trying to marshal the memory file, I am getting following exception.
Any clue?
javax.xml.bind.PropertyException: name: com.sun.xml.bind.namespacePrefixMapper value: de.micromata.opengis.kml.v_2_2_0.Kml$NameSpaceBeautyfier#1cfa4b2
at javax.xml.bind.helpers.AbstractMarshallerImpl.setProperty(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.setProperty(Unknown Source)
at de.micromata.opengis.kml.v_2_2_0.Kml.createMarshaller(Kml.java:642)
at de.micromata.opengis.kml.v_2_2_0.Kml.marshal(Kml.java:682)
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 sun.reflect.misc.Trampoline.invoke(Unknown Source)
at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.MethodUtil.invoke(Unknown Source)

When using the com.sun.xml.bind.namespacePrefixMapper you need to ensure that you have the JAXB RI (or EclipseLink JAXB (MOXy) on your class path.
The JDK contains a package renamed version of the JAXB RI so you could try the following property name instead:
com.sun.xml.internal.bind.namespacePrefixMapper
For More Information
http://blog.bdoughan.com/2011/11/jaxb-and-namespace-prefixes.html

faultString: java.lang.IllegalArgumentException: argument type mismatch

I am trying to give web service call using Axis genrated stub.
It is running giving below exception when it tryies to get respons.
and when i view my response message using :
String responseMsg = stub._getCall().getMessageContext().getResponseMessage().getSOAPEnvelope().toString();
System.out.println(responseMsg);
it is giving the correct response in SOAP format. can anybody help me where it is creating issue thanks in Advance.
Zuned
AxisFault
faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException
faultSubcode:
faultString: java.lang.IllegalArgumentException: argument type mismatch
faultActor:
faultNode:
faultDetail:
{http://xml.apache.org/axis/}stackTrace:java.lang.IllegalArgumentException: argument type mismatch
at org.apache.axis.encoding.ser.BeanPropertyTarget.set(BeanPropertyTarget.java:157)
at org.apache.axis.encoding.DeserializerImpl.valueComplete(DeserializerImpl.java:249)
at org.apache.axis.encoding.DeserializerImpl.endElement(DeserializerImpl.java:509)
at org.apache.axis.encoding.DeserializationContext.endElement(DeserializationContext.java:1087)
at org.apache.axis.message.SAX2EventRecorder.replay(SAX2EventRecorder.java:171)
at org.apache.axis.message.MessageElement.publishToHandler(MessageElement.java:1141)
at org.apache.axis.message.RPCElement.deserialize(RPCElement.java:236)
at org.apache.axis.message.RPCElement.getParams(RPCElement.java:384)
at org.apache.axis.client.Call.invoke(Call.java:2467)
at org.apache.axis.client.Call.invoke(Call.java:2366)
at org.apache.axis.client.Call.invoke(Call.java:1812)
at com.hps.webservice.SOAPInterfaceBindingStub.getStatus(SOAPInterfaceBindingStub.java:852)
at com.hps.ws.HPSStatusManagerJob.getApplicationStatusResponse(HPSStatusManagerJob.java:265)
at com.hps.ws.HPSStatusManagerJob.updateStatus(HPSStatusManagerJob.java:84)
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 org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273)
at org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean$MethodInvokingJob.executeInternal(MethodInvokingJobDetailFactoryBean.java:264)
at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:525)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
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 org.apache.axis.utils.BeanPropertyDescriptor.set(BeanPropertyDescriptor.java:142)
at org.apache.axis.encoding.ser.BeanPropertyTarget.set(BeanPropertyTarget.java:75)
... 22 more
{http://xml.apache.org/axis/}hostname:admin-PC
java.lang.IllegalArgumentException: argument type mismatch
at org.apache.axis.AxisFault.makeFault(AxisFault.java:101)
at org.apache.axis.client.Call.invoke(Call.java:2470)
at org.apache.axis.client.Call.invoke(Call.java:2366)
at org.apache.axis.client.Call.invoke(Call.java:1812)
at com.hps.webservice.SOAPInterfaceBindingStub.getStatus(SOAPInterfaceBindingStub.java:852)
at com.hps.ws.HPSStatusManagerJob.getApplicationStatusResponse(HPSStatusManagerJob.java:265)
at com.hps.ws.HPSStatusManagerJob.updateStatus(HPSStatusManagerJob.java:84)
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 org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273)
at org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean$MethodInvokingJob.executeInternal(MethodInvokingJobDetailFactoryBean.java:264)
at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:525)
Caused by: java.lang.IllegalArgumentException: argument type mismatch
at org.apache.axis.encoding.ser.BeanPropertyTarget.set(BeanPropertyTarget.java:157)
at org.apache.axis.encoding.DeserializerImpl.valueComplete(DeserializerImpl.java:249)
at org.apache.axis.encoding.DeserializerImpl.endElement(DeserializerImpl.java:509)
at org.apache.axis.encoding.DeserializationContext.endElement(DeserializationContext.java:1087)
at org.apache.axis.message.SAX2EventRecorder.replay(SAX2EventRecorder.java:171)
at org.apache.axis.message.MessageElement.publishToHandler(MessageElement.java:1141)
at org.apache.axis.message.RPCElement.deserialize(RPCElement.java:236)
at org.apache.axis.message.RPCElement.getParams(RPCElement.java:384)
at org.apache.axis.client.Call.invoke(Call.java:2467)
... 14 more
Caused by: java.lang.IllegalArgumentException: argument type mismatch
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 org.apache.axis.utils.BeanPropertyDescriptor.set(BeanPropertyDescriptor.java:142)
at org.apache.axis.encoding.ser.BeanPropertyTarget.set(BeanPropertyTarget.java:75)
... 22 more

one more way to generate file as in my case axis 1.4 was not working because of compatibility issue(not sure what it is). we can use wsimport.exe inbuilt in jdk to generate stub
go to your jdk bin folder and run command wsimport -s destinationPath WSDL path
as:
C:\Program Files\Java\jdk1.6.0\bin>wsimport -s C:\sid\ http://?WSDL
after that copy paste generated folder structure and classes

The Problem was the local WSDL was not updated so I first updated the local WSDL and then genrated the classes once again .
:)

JAX-WS on Tomcat server

I am trying to deploy a JAX-WS on a Tomcat server. I have looked around the web and followed instructions I found here and here but to no avail. I get the following error and have no idea how to correct the issue.
SEVERE: WSSERVLET11: failed to parse runtime descriptor: java.lang.NoClassDefFoundError: javax/xml/stream/XMLStreamException java.lang.NoClassDefFoundError: javax/xml/stream/XMLStreamException
at com.sun.xml.ws.transport.http.servlet.WSServletContextListener.contextInitialized(WSServletContextListener.java:103)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3827)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4343)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:823)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:807)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:595)
at org.apache.catalina.core.StandardHostDeployer.addChild(StandardHostDeployer.java:903)
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 org.apache.commons.beanutils.MethodUtils.invokeMethod(MethodUtils.java:216)
at org.apache.commons.digester.SetNextRule.end(SetNextRule.java:256)
at org.apache.commons.digester.Rule.end(Rule.java:276)
at org.apache.commons.digester.Digester.endElement(Digester.java:1058)
at org.apache.catalina.util.CatalinaDigester.endElement(CatalinaDigester.java:76)
at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
at org.apache.xerces.parsers.AbstractXMLDocumentParser.emptyElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.emptyElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.commons.digester.Digester.parse(Digester.java:1567)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:488)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:863)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:483)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:427)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:983)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:349)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1091)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:789)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1083)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:478)
at org.apache.catalina.core.StandardService.start(StandardService.java:480)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2313)
at org.apache.catalina.startup.Catalina.start(Catalina.java:556)
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 org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:287)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:425)
- Error listenerStart
- Context startup failed due to previous errors
Jun 30, 2011 10:04:25 AM com.sun.xml.ws.transport.http.servlet.WSServletContextListener contextDestroyed
INFO: WSSERVLET13: JAX-WS context listener destroyed
here is my sun-jaxws.xml file
<?xml version="1.0" encoding="UTF-8"?> <endpoints xmlns="http://java.sun.com/xml.ns/jax-ws/ri/runtime" version="2.0">
<endpoint name="ActionMutatorProxy" implementation="com.hyr.boa.transport.ActionMutatorProxy" url-pattern="/action_mutator_proxy" />

A NoClassDefFoundError thrown at deploy time means that a class definition that was present on the build path (e.g. the Java code compiles) cannot be found at runtime. The compile-time class path is not the same as the deploy-time class path with Tomcat (and other containers).
You need to put jaxp-api.jar into WEB-INF/lib or $CATALINA_HOME/lib.

Casting problems with Google Maps API

I'm trying to run the following line:
Directions.loadFromWaypoints((Waypoint[])waypoints.toArray(), opts);
But I'm getting:
23:41:44.595 [ERROR] [carathome] Uncaught exception escaped
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Lcom.google.gwt.maps.client.geocode.Waypoint;
at com.presasystems.gwt.carathome.client.widgets.MostrarLinhasPanel$1$1.onSuccess(MostrarLinhasPanel.java:72)
at com.presasystems.gwt.carathome.client.widgets.MostrarLinhasPanel$1$1.onSuccess(MostrarLinhasPanel.java:1)
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:216)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:393)
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.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157)
at com.google.gwt.dev.shell.BrowserChannel.reactToMessagesWhileWaitingForReturn(BrowserChannel.java:1713)
at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:165)
at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:120)
at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:507)
at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:264)
at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:188)
at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157)
at com.google.gwt.dev.shell.BrowserChannel.reactToMessages(BrowserChannel.java:1668)
at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:401)
at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:222)
at java.lang.Thread.run(Unknown Source)
Why? Shouldn't this cast work? How can I do this in an elegant fashion?
Thanks in advance

Try
Directions.loadFromWaypoints((Waypoint[])(waypoints.toArray()), opts);
Alternatively
Waypoint[] array = new Waypoint[0];
array = waypoints.toArray(array);
Directions.loadFromWaypoints(array, opts);
Or more simply
Waypoint[] array = waypoints.toArray(new Waypoint[0]);
Directions.loadFromWaypoints(array, opts);
See also List#toArray(T[] a).
Addendum: Initially, I thought your cast was a precedence problem. The generic parameter T in List#toArray(T[] a) eliminates the need for an explicit cast by ensuring that the "runtime type of the returned array is that of the specified array." In effect, it "acts as bridge between array-based and collection-based APIs."