Picker throws exception when selecting a document

[jesubiag]

After opening the picker and picking a document, when the picker closes, it throws the following exception:

java.lang.AbstractMethodError: org.vaadin.addon.googlepicker.GooglePicker$1.call(Lelemental/json/JsonArray;)V
    at com.vaadin.server.JavaScriptCallbackHelper$1.call(JavaScriptCallbackHelper.java:80)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:168)
    at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:118)
    at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:291)
    at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:184)
    at com.vaadin.server.communication.PushHandler$3.run(PushHandler.java:174)
    at com.vaadin.server.communication.PushHandler.callWithUi(PushHandler.java:253)
    at com.vaadin.server.communication.PushHandler.access$200(PushHandler.java:56)
    at com.vaadin.server.communication.PushHandler$1.onRequest(PushHandler.java:76)
    at org.atmosphere.cpr.AsynchronousProcessor.action(AsynchronousProcessor.java:205)
    at org.atmosphere.cpr.AsynchronousProcessor.suspended(AsynchronousProcessor.java:104)
    at org.atmosphere.container.TomcatWebSocketUtil.doService(TomcatWebSocketUtil.java:154)
    at org.atmosphere.container.Tomcat7Servlet30SupportWithWebSocket.service(Tomcat7Servlet30SupportWithWebSocket.java:62)
    at org.atmosphere.cpr.AtmosphereFramework.doCometSupport(AtmosphereFramework.java:2075)
    at org.atmosphere.websocket.DefaultWebSocketProcessor.dispatch(DefaultWebSocketProcessor.java:570)
    at org.atmosphere.websocket.DefaultWebSocketProcessor$3.run(DefaultWebSocketProcessor.java:332)
    at org.atmosphere.util.VoidExecutorService.execute(VoidExecutorService.java:101)
    at org.atmosphere.websocket.DefaultWebSocketProcessor.dispatch(DefaultWebSocketProcessor.java:327)
    at org.atmosphere.websocket.DefaultWebSocketProcessor.invokeWebSocketProtocol(DefaultWebSocketProcessor.java:424)
    at org.atmosphere.websocket.DefaultWebSocketProcessor.dispatchReader(DefaultWebSocketProcessor.java:794)
    at org.atmosphere.websocket.DefaultWebSocketProcessor.invokeWebSocketProtocol(DefaultWebSocketProcessor.java:526)
    at org.atmosphere.container.TomcatWebSocketHandler.onTextData(TomcatWebSocketHandler.java:104)
    at org.apache.catalina.websocket.StreamInbound.doOnTextData(StreamInbound.java:191)
    at org.apache.catalina.websocket.StreamInbound.onData(StreamInbound.java:139)
    at org.apache.coyote.http11.upgrade.UpgradeProcessor.upgradeDispatch(UpgradeProcessor.java:88)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:621)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

Project setup is Vaadin 7.4.0, Tomcat 7.0.65 and GooglePicker for Vaadin both 1.0.0 and 1.0.1 (none of them work).
The picker used to work with this setup. No change was made to my project source since a long time. Suddenly, when i retook this project, i found out picker wasn't working anymore.

This is how picker is called

picker.addSelectionListener(new GooglePicker.SelectionListener() {
            private static final long serialVersionUID = 1L;

            @Override
            public void documentSelected(GooglePicker.Document document) {
                 String pickerName = document.getName();
                 String pickerDir = document.getUrlString();
                 UploadFiles uploadWindow = new UploadFiles(subjectName, type, view, pickerName, pickerDir);
                 addWindow(uploadWindow);
            }

            //Aca elegimos que hacer con el archivo que selecciona el usuario
            //En nuestro caso obtenemos el nombre y la URL

       });
       addExtension(picker);
       // Abre el picker de Google que muestra las carpetas de drive del usuario
       picker.pickDocument(GooglePicker.Type.DOCS);