Error handling patterns in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a try-catch block used for in Kotlin Android development?

A try-catch block is used to handle exceptions that might occur during code execution, preventing the app from crashing and allowing graceful error recovery.

intermediate

What does the finally block do in Kotlin error handling?

The finally block contains code that always runs after try and catch blocks, whether an exception occurred or not. It's often used to clean up resources like closing files or network connections.

intermediate

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

Kotlin does not have checked exceptions like Java. All exceptions are unchecked, meaning the compiler does not force you to catch or declare them. You decide where to handle exceptions.

advanced

What is the purpose of using sealed classes for error handling in Kotlin?

Sealed classes let you define a fixed set of error types, making it easier to <strong>handle different error cases explicitly</strong> with when expressions, improving code safety and readability.

intermediate

Why should you avoid catching generic Exception in Android apps?

Catching generic Exception can hide unexpected errors and make debugging harder. It's better to catch specific exceptions to handle known error cases clearly and avoid masking bugs.

Which Kotlin keyword is used to catch exceptions?

A throw

B handle

C try

D catch

The catch block is used to catch exceptions thrown in the try block.

What block runs regardless of whether an exception occurs or not?

A catch

B finally

C try

D throw

The finally block always runs after try and catch blocks.

In Kotlin, are exceptions checked or unchecked?

A Unchecked

B Checked

C Both

D Neither

Kotlin exceptions are unchecked, so the compiler does not force handling them.

What Kotlin feature helps define a fixed set of error types?

A Data classes

B Interfaces

C Sealed classes

D Enums

Sealed classes allow defining a closed set of subclasses, useful for error types.

Why avoid catching generic Exception in Android apps?

A It hides unexpected errors

B It improves performance

C It is required by Kotlin

D It prevents all crashes

Catching generic Exception can hide bugs and make debugging difficult.

Describe how you would use try-catch-finally blocks to handle errors in an Android Kotlin app.

Think about what code might fail, how to catch errors, and cleaning up resources.

Explain the benefits of using sealed classes for error handling compared to just using exceptions.

Consider how sealed classes help organize and handle errors explicitly.