vaadin msg WARNING: Tried to unregister

Question

com.vaadin.ui.ConnectorTracker unregisterConnector WARNING: Tried to unregister (83) which is not registered

here is my code causing this warning. It does a simple component replace with applet component addon.

On click of a button calls appletConponent.handleClick()

the applet works, but I see the warning msg in the logs.

    static class AppletComponent extends  CustomComponent{
    Component  appletComponent;
    VerticalLayout  container;
    String contextRoot;

    void construct(){
        container= new VerticalLayout();
        setCompositionRoot(container);
        contextRoot=VaadinServlet.getCurrent().getServletContext().getContextPath();
        // initialize with empty component
        container.addComponent(appletComponent= new Label());
    }
    void handleClick(){
            addApplet();
        }
    }

    void addApplet(){
        try{
            String appletParam=gatesSession.getPathParameter();
            Component  oldComponent=appletComponent;
            Component  newComponent=new AppletIntegration() {
                private static final long serialVersionUID = 1L;
                @Override
                public void attach() {
                    // applet codebase,archive url 
                }
          };
          container.replaceComponent(oldComponent, newComponent);
          appletComponent= newComponent;
        }catch(Exception e){
            logger.error(" could not create session ",e);
            Notification.show("Cannot Launch  ","failed"+ e.getMessage(),Type.ERROR_MESSAGE);
        }
    }

Answer 1

When overriding component's attach() method remember to call super.attach() as well:

@Override
public void attach() {
    super.attach(); // Don't forget this!
}

The same applies to detach().