A `FileUriExposedException` in the Android operating system arises when an application attempts to share a `file://` URI outside of its own process boundaries. Specifically, this typically occurs when passing such a URI through an `Intent`, particularly via methods like `getData()`, to another application. The issue stems from the receiving application potentially gaining access to a file path that it should not have permission to access directly. For instance, an application could create a `file://` URI pointing to a sensitive data file within its private storage and then inadvertently expose this URI to another application through an `Intent`.
This exception is important because it addresses a significant security and privacy risk. Prior to Android 7.0 (API level 24), applications could freely share `file://` URIs. However, this practice proved problematic, as it allowed malicious applications to potentially infer and access file paths within other applications’ private storage, circumventing Android’s permission model. The introduction of this exception and the encouragement to use `content://` URIs, facilitated by `FileProvider`, aimed to mitigate these risks by enforcing stricter access controls and providing a more secure mechanism for inter-application file sharing.