Exception Handling

1. What is an exception in Kotlin?

An exception is an event that occurs during the execution of a program, disrupting the normal flow of instructions.

2. How are exceptions represented in Kotlin?

Exceptions in Kotlin are represented by classes that inherit from the Throwable class.

3. Explain the difference between checked and unchecked exceptions in Kotlin.

Checked exceptions are checked at compile-time, and unchecked exceptions are not checked at compile-time.

4. How do you catch an exception in Kotlin?

Using the try, catch, and finally blocks:

5. What is the purpose of the finally block in exception handling?

The finally block contains code that is executed whether an exception is thrown or not, making it useful for cleanup operations.

6. How are multiple catch blocks handled in Kotlin?

The catch blocks are evaluated from top to bottom, and the first one with a matching exception type is executed.

7. Explain the try expression in Kotlin.

The try expression is an expression-based form of the try block, allowing you to use it in assignments:

8. How can you define a custom exception in Kotlin?

9. What is the difference between throw and throw e in exception handling?

throw is used to throw a new exception, while throw e is used to rethrow the caught exception.

10. Explain the @Throws annotation in Kotlin.

The @Throws annotation is used to declare that a function may throw a specified exception.

11. How can you use the use function for resource management in Kotlin?

The use function is an extension function on Closeable resources and ensures that the resource is closed when the block is exited.

12. Explain the concept of nullable exceptions in Kotlin.

In Kotlin, exceptions are non-nullable by default. However, you can use the as? operator to catch nullable exceptions.

13. What is the purpose of the finally expression in Kotlin 1.7?

The finally expression allows you to use the result of the try block or the catch block within the finally block.

14. How can you handle multiple exceptions in a single catch block in Kotlin?

You can use the | operator to catch multiple exceptions in a single catch block.

15. Explain the noinline modifier in Kotlin exception handling.

The noinline modifier is used to prevent a lambda expression from being inlined, making it suitable for use in exception handling.

16. How does the Suppressed feature in Kotlin exception handling work?

The Suppressed feature allows you to suppress exceptions that occur during cleanup operations, ensuring that the original exception is not lost.

17. Explain the runCatching function in Kotlin.

The runCatching function is a safer way to perform operations that may throw exceptions and handle them using the onSuccess, onFailure, and getOrNull functions.

18. How can you handle exceptions in a functional programming style in Kotlin?

You can use higher-order functions like runCatching, onSuccess, and onFailure to handle exceptions in a more functional manner.

19. What is the role of the UncaughtExceptionHandler in Kotlin?

The UncaughtExceptionHandler allows you to set a global exception handler for uncaught exceptions in a thread.

20. How can you create a custom exception handler for the entire application in Kotlin?

By setting a custom UncaughtExceptionHandler using Thread.setDefaultUncaughtExceptionHandler.