I got this while debugging a application with FileUploadHandler in eclipse with Vaadin 7.4.1…
Maybe a null check is required?
java.lang.NullPointerException
at com.vaadin.ui.ConnectorTracker.cleanStreamVariable(ConnectorTracker.java:845)
at com.vaadin.server.communication.FileUploadHandler$1.run(FileUploadHandler.java:695)
at com.vaadin.server.VaadinSession.accessSynchronously(VaadinSession.java:1324)
at com.vaadin.server.communication.FileUploadHandler.cleanStreamVariable(FileUploadHandler.java:692)
at com.vaadin.server.communication.FileUploadHandler.handleFileUploadValidationAndData(FileUploadHandler.java:459)
at com.vaadin.server.communication.FileUploadHandler.doHandleXhrFilePost(FileUploadHandler.java:510)
at com.vaadin.server.communication.FileUploadHandler.handleRequest(FileUploadHandler.java:291)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1409)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:364)