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.M开发者_Go百科oduleSpace.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."