try catch Block in Kotlin

Introduction

try catch 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.

Try-catch handles runtime errors and prevents program crash. 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

• try-catch handles runtime errors and prevents program crash.
• Code that may fail is placed inside the try block.
• The catch block runs when a matching exception occurs.

Syntax

try {
    // risky code
} catch (e: Exception) {
    // handle
}

try catch Block in Kotlin Example Program in Kotlin

fun main(args: Array<String>) {
    try {
        val number = "ABC".toInt()
        println(number)
    } catch (e: NumberFormatException) {
        println("Invalid number format")
    }
}

Sample Output

Invalid number format

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 number = "ABC".toInt() assigns or updates a value used later in the program.

3. The println(number) statement writes a line to the console — this produces part of the sample output below.

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

5. Try-catch handles runtime errors and prevents program crash.

6. 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

• try-catch handles runtime errors and prevents program crash.
• Code that may fail is placed inside the try block.
• The catch block runs when a matching exception occurs.
• 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.