> Markdown version of [Finding The Current UI And Page And Vaadin Session](https://vaadin.com/docs/v8/framework/articles/FindingTheCurrentUIAndPageAndVaadinSession). Section index: [llms.txt](https://vaadin.com/docs/v8/framework/llms.txt)

# <a id="finding-the-current-ui-and-page-and-vaadin-session"></a>Finding the current UI and page and vaadin session

There are many cases where you need a reference to the active `UI`, `Page` or `VaadinServiceSession`, for instance for showing notifications in a click listener. It is possible to get a reference to the component from the event and then a reference from the component to the UI but Vaadin also offers an easier way through two static methods:

```java
UI.getCurrent()
Page.getCurrent()
VaadinSession.getCurrent()
```

For example when you want to show the name of the current UI class:

```java
Button helloButton = new Button("Say Hello");
    helloButton.addClickListener(new ClickListener() {
        @Override
        public void buttonClick(ClickEvent event) {
            Notification.show("This UI is "
                    + UI.getCurrent().getClass().getSimpleName());
        }
    });
```

Similarly for `VaadinServiceSession`, for instance to find out if the application is running in production mode:

```java
public void buttonClick(ClickEvent event) {
    String msg = "Running in ";
    msg += VaadinSession.getCurrent().getConfiguration()
            .isProductionMode() ? "production" : "debug";
    Notification.show(msg);
}
```

And finally similarly for `Page`. For instance adding a browser window resize listener can be added like this:

```java
Page.getCurrent().addBrowserWindowResizeListener(
  new Page.BrowserWindowResizeListener() {
    @Override
    public void browserWindowResized(BrowserWindowResizeEvent event) {
      Notification.show("Browser resized to " + event.getWidth() + "x" + event.getHeight());
    }
});
```

**Note** that these are based on `ThreadLocal` so they won’t work in a background thread (or otherwise outside the standard request scope).