How does the Android system handle configuration changes like screen rotations?

When the Android system encounters a configuration change such as a screen rotation, it manages this by restarting the activity. During this process, the system calls the onCreate() method again, which allows the activity to be recreated with the appropriate resources for the new configuration. This behavior ensures that the user interface adapts to the current orientation while maintaining a fresh state of the activity.

The activity's lifecycle is designed to accommodate these changes seamlessly. When the change occurs, the system saves the current state of the activity (using mechanisms like onSaveInstanceState()) and then destroys the existing instance before creating a new one. This process allows the new instance to initialize with the updated configuration parameters, ensuring that the activity displays correctly for the user.

Understanding this lifecycle behavior is crucial for developers, as it helps them implement necessary adjustments to the activity to maintain user experience effectively. While the developer can choose to handle configuration changes manually (e.g., by declaring in the manifest that they want to handle configuration changes), the default behavior of restarting the activity and calling onCreate() is the standard approach used by Android.