finally Block in Kotlin

Introduction

finally Block is a fundamental concept every Kotlin developer should understand. Exceptions signal that something went wrong at runtime. Kotlin treats checked exceptions differently from Java, encouraging explicit error handling where it matters.

Finally block always executes after try and catch. In this tutorial you will learn the syntax, walk through a complete example program, study the sample output, and review best practices so you can apply the concept confidently in your own projects.

Definition

• finally block always executes after try and catch.
• It is used for cleanup actions such as closing resources.
• finally runs whether or not an exception occurred.

Syntax

try { } catch (e: Exception) { } finally { }

finally Block in Kotlin Example Program in Kotlin

fun main(args: Array<String>) {
    try {
        val result = 10 / 2
        println("Result: $result")
    } catch (e: ArithmeticException) {
        println("Math error")
    } finally {
        println("Execution completed")
    }
}

Sample Output

Result: 5
Execution completed

When to use

Use try/catch when calling code that can fail — file access, network calls, parsing — and you need a controlled recovery path.

How it works

1. The program starts with a main function — the entry point that runs when you execute the file.

2. val result = 10 / 2 assigns or updates a value used later in the program.

3. The println("Result: $result") statement writes a line to the console — this produces part of the sample output below.

4. The println("Math error") statement writes a line to the console — this produces part of the sample output below.

5. The println("Execution completed") statement writes a line to the console — this produces part of the sample output below.

6. Finally block always executes after try and catch.

7. Run the program in IntelliJ IDEA, Android Studio, or with the Kotlin command-line compiler (kotlinc / kotlin). Compare your console output with the sample output shown below.

Best Practices

Common Mistakes

Key Points

• finally block always executes after try and catch.
• It is used for cleanup actions such as closing resources.
• finally runs whether or not an exception occurred.
• Test the example locally and verify the output matches the sample.
• Experiment by changing input values to see how behaviour changes.

Notes

• Semicolons at the end of statements are optional in Kotlin.