Quick Intro to the Kotlin world.

1. How to become a Kotlin
developer in 10 mins

2. Kotlin
• Statically Typed
• Cross-platform
• Made by JetBrains
• Concise

3. Concise
/
*
Create a POJO with getters, setters,
`equals()`, `hashCode()`, `toString()` and
`copy()` in a single line:
*
/
data class Customer(
val name: String,
val email: String,
val company: String,
)

4. Concise
/
/
Or filter a list using a lambda expression:
val positiveNumbers = list.filter { it > 0 }

5. Concise
/
/
Want a singleton? Create an object:
object ThisIsASingleton {
val companyName: String = "JetBrains"
}

6. Kotlin
• Statically Typed
• Cross-platform
• Made by JetBrains
• Concise
• Safe

7. Safe
/
*
Get rid of those pesky NullPointerExceptions,
you know, The Billion Dollar Mistake
*
/
var output: String
output = null
/
/
Compilation error
/
/
Kotlin protects you from mistakenly operating on nullable types
val name: String? = null
/
/
Nullable type
println(name.length())
/
/
Compilation error

8. Kotlin
• Statically Typed
• Cross-platform
• Made by JetBrains
• Concise
• Safe
• Tool-friendly
• Interoperable

9. Interoperable
import io.reactivex.rxjava3.core.Flowable
import io.reactivex.rxjava3.schedulers.Schedulers
fun main() {
Flowable
.fromCallable {
Thread.sleep(1000)
/
/
imitate expensive computation
"Done"
}
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.single())
.subscribe(
:
:
println, Throwable
:
:
printStackTrace)
}

10. Kotlin for server-side

11. There is more…
•Default values for function parameters
•String Interpolation
•Instance Checks
•Ranges
•Extension Functions
•‘try/catch’ and ‘if’ expressions
•Single-expression functions
•…

12. More info
•kotlinlang.org
•Kotlin for server-side
•Kotlin Koans
•Kotlin Vocabulary

13. Thank You!