Why generics provide type safety in Kotlin - See It in Action

Why generics provide type safety

📖 Scenario: Imagine you are organizing a library where you want to keep track of books by their titles. You want to make sure that only book titles (strings) are stored in your list to avoid confusion.

🎯 Goal: You will create a list that only accepts strings using generics in Kotlin. This will help you understand how generics provide type safety by preventing wrong data types from being added.

📋 What You'll Learn

Create a list of strings using Kotlin generics

Add some book titles to the list

Try to add a number to the list (commented out to avoid error)

Print the list to see the stored book titles

💡 Why This Matters

🌍 Real World

Using generics helps avoid bugs in apps by making sure data is the right type, like keeping only book titles in a list of books.

💼 Career

Understanding generics and type safety is important for writing clean, error-free Kotlin code in professional Android or backend development.

1

Create a list of book titles

Create a variable called bookTitles that is a mutable list of strings using Kotlin generics.

Kotlin

// Create a mutable list of strings called bookTitles
// Your code here

Need a hint?

Use MutableList<String> to specify a list that only holds strings.

2

Add book titles to the list

Add the strings "Kotlin Basics" and "Advanced Kotlin" to the bookTitles list using the add method.

Kotlin

val bookTitles: MutableList = mutableListOf()
// Add "Kotlin Basics" and "Advanced Kotlin" to bookTitles
// Your code here

Need a hint?

Use bookTitles.add("Your Title") to add each book title.

3

Try to add a number to the list (type safety)

Add a commented out line that tries to add the number 123 to the bookTitles list to show that Kotlin prevents adding wrong types.

Kotlin

val bookTitles: MutableList = mutableListOf()
bookTitles.add("Kotlin Basics")
bookTitles.add("Advanced Kotlin")
// Add a commented out line to add number 123 to bookTitles
// Your code here

Need a hint?

Comment out the line with // to show it causes an error if uncommented.

4

Print the list of book titles

Print the bookTitles list using println to show the stored book titles.

Kotlin

val bookTitles: MutableList = mutableListOf()
bookTitles.add("Kotlin Basics")
bookTitles.add("Advanced Kotlin")
// bookTitles.add(123) // This line is commented out because it causes a type error
// Print the bookTitles list
// Your code here

Need a hint?

Use println(bookTitles) to display the list.