> Markdown version of [Exception Handling](https://vaadin.com/docs/next/tools/swing/exceptions). Section index: [llms.txt](https://vaadin.com/docs/next/tools/llms.txt)

# Exception Handling

Any exception not handled by the remote View is by default handled by Swing. Further, Swing shows the exception in a `JOptionPane`. This behaviour can be configured to catch any Vaadin exceptions from Swing, directly.

## <a id="custom-handling"></a>Custom Handling

A custom handler for the exception can be used after disabling the default behaviour with the following:

```java
vaadinPanel.disableDefaultExceptionHandler();
```

Add a custom exception handler by adding the following:

```java
vaadinPanel.addEventListener(EventType.EXCEPTION, event -> {
    // Print to standard output the exception content
    System.out.println(event.getParams().get("content"));
});
```

Notice, that the event contains only `String` values instead of the original `Exception`. This is to avoid serialization errors due to different classpaths from the Vaadin application and the Swing application.