ApplicationExceptionHandler class

A global, thread-safe handler for uncaught exceptions in JetLeaf applications.

The ApplicationExceptionHandler is responsible for intercepting all uncaught exceptions thrown during the execution of the application, either synchronously or asynchronously (within Zones). It ensures that exceptions are:

1. Wrapped consistently: Non-Throwable objects (e.g., Exception, Error) are wrapped into RuntimeException for uniform handling.
2. De-duplicated: Exceptions are tracked internally to avoid logging the same exception multiple times, including nested causes.
3. Delegated: Optionally forwarded to a parent handler provided via the constructor for integration with external logging or error handling frameworks.
4. Terminating gracefully: Supports registering a custom exit code that terminates the application when a critical exception occurs.
5. Recognized: Known logging-related errors (see _logConfigurationMessages) are detected and treated specially.

Thread-local storage (_handlerLocal) ensures that each Dart isolate can maintain its own handler, providing isolated exception handling per execution context. Use current to access the handler in the current isolate.

Example Usage

void main() {
  final handler = ApplicationExceptionHandler.current;
  
  runZonedGuarded(() {
    throw Exception("Something went wrong!");
  }, handler.uncaughtException);
}

References:

• Throwable: Base class for exceptions in JetLeaf.
• RuntimeException: Wrapper for non-Throwable objects.
• Zone: Dart class for asynchronous exception handling.
• _logConfigurationMessages: Recognized log configuration error messages.