How should error and exception handling be properly implemented in an application?

Proper error and exception handling in an application includes several key points:

1. Local handling: catch exceptions where they can be properly managed or recovered.
2. Logging: record error information for later analysis.
3. User notification: show understandable and helpful messages without revealing internal details.
4. Do not suppress exceptions without reason: if an error is critical, it should be either handled or propagated upwards.
5. Use specialized exception types: apply different exception classes for different errors.

Example in Java:

try {
    // code that may throw an exception
    processData();
} catch (IOException e) {
    logger.error("Error processing data", e);
    showErrorToUser("Failed to process data. Please try again later.");
} finally {
    cleanUpResources();
}

This approach ensures application stability and ease of maintenance.