RunCatching for safe execution in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is RunCatching in Kotlin?

runCatching is a Kotlin function that helps you run code safely by catching exceptions automatically. It wraps the code block and returns a Result object that holds either the success value or the exception.

beginner

How do you get the successful result from a RunCatching block?

You can use getOrNull() to get the result if it succeeded, or null if there was an exception. Alternatively, use getOrElse { defaultValue } to provide a fallback value.

intermediate

What does onFailure do when used with RunCatching?

onFailure lets you run code only if the runCatching block caught an exception. It is useful for logging errors or handling failures without stopping the program.

beginner

Write a simple example of RunCatching that safely divides two numbers and returns 0 if division fails.

val result = runCatching { 10 / 0 }.getOrElse { 0 }
println(result) // Output: 0

intermediate

Why is RunCatching preferred over traditional try-catch blocks?

runCatching makes code cleaner and more readable by wrapping try-catch logic into a single expression. It also provides useful functions to handle success and failure in a functional style.

What does runCatching return after executing a block?

A A Result object containing success or failure

B The raw value or throws exception

C Always null

D Boolean true or false

runCatching returns a Result object that holds either the successful value or the caught exception.

Which function gets the value or returns a default if there was an exception?

A getOrNull()

B getOrElse { default }

C onFailure { }

D runCatching { }

getOrElse { default } returns the success value or the default if an exception occurred.

How can you run code only when runCatching catches an exception?

A Using onSuccess { }

B Using getOrElse { }

C Using onFailure { }

D Using getOrNull()

onFailure { } runs only if the block caught an exception.

What will runCatching { 5 / 0 }.getOrNull() return?

A null

B 0

C 5

D Throws exception

Division by zero throws an exception, so getOrNull() returns null.

Which is NOT a benefit of using runCatching?

A Cleaner code than try-catch

B Functional style error handling

C Easy chaining of success/failure handlers

D Automatically fixes bugs

runCatching does not fix bugs automatically; it only helps handle exceptions safely.

Explain how runCatching helps in safe execution of code in Kotlin.

Think about how it replaces try-catch and what it returns.

Describe how you can handle both success and failure cases using runCatching.

Consider the functions available on the Result object.