Nice to meet you Kotlin

Kotlin has been announced as a first class language for Android developement by Google at the Google I/O 2017. This talk presents Kotlin as a mature and production ready language to migrate all Android projects from Java to Kotlin.

Transcript

1. NICE TO MEET YOU Gerard Paligot
2. KOTLIN
3. KOTLIN
4. KOTLIN
5. KOTLIN
6. KOTLIN
7. KOTLIN Presentation
8. KOTLIN - Started in mid 2010 Presentation
9. KOTLIN - Started in mid 2010 - Avoid huge Java codebase Presentation
10. KOTLIN - Started in mid 2010 - Avoid huge Java codebase - Building tools for many languages Presentation
11. KOTLIN - Started in mid 2010 - Avoid huge Java codebase - Building tools for many languages - Want a modern, expressive language Presentation
12. KOTLIN - Started in mid 2010 - Avoid huge Java codebase - Building tools for many languages - Want a modern, expressive language - Easy to introduce in the existing environment Presentation
13. KOTLIN Design Goals
14. KOTLIN - Full Java interoperability Design Goals
15. KOTLIN - Full Java interoperability - Compile as fast as Java Design Goals
16. KOTLIN - Full Java interoperability - Compile as fast as Java - More concise than Java Design Goals
17. KOTLIN - Full Java interoperability - Compile as fast as Java - More concise than Java - Prevent more kinds of errors than Java Design Goals
18. KOTLIN - Full Java interoperability - Compile as fast as Java - More concise than Java - Prevent more kinds of errors than Java - Was simpler than Scala Design Goals
19. WHY USE KOTLIN?
20. WHY USE KOTLIN?
21. WHY USE KOTLIN? - In a future, will replace Java as first language
22. WHY USE KOTLIN? - In a future, will replace Java as first language - High adoption of the Android community
23. WHY USE KOTLIN? - In a future, will replace Java as first language - High adoption of the Android community - Easy learning for iOS and Android developers
24. WHY USE KOTLIN? - In a future, will replace Java as first language - High adoption of the Android community - Easy learning for iOS and Android developers - Null safety
25. WHY USE KOTLIN? - In a future, will replace Java as first language - High adoption of the Android community - Easy learning for iOS and Android developers - Null safety - Less code is better!
26. WHY USE KOTLIN? - In a future, will replace Java as first language - High adoption of the Android community - Easy learning for iOS and Android developers - Null safety - Less code is better! - Compilation speed
27. WHY USE KOTLIN? High adoption of the Android community
28. WHY USE KOTLIN? Compilation speed
29. WHY USE KOTLIN? Compilation speed Deamon Gradle deactivated
30. WHY USE KOTLIN? Compilation speed Deamon Gradle activated
31. WHY USE KOTLIN? Compilation speed One isolated file changed
32. WHY USE KOTLIN? Compilation speed One file changed
33. ONE MORE THING…
34. KOTLIN IS AVAILABLE ON…
35. KOTLIN IS AVAILABLE ON…
36. KOTLIN IS AVAILABLE ON…
37. KOTLIN IS AVAILABLE ON…
38. KOTLIN IS AVAILABLE ON…
39. KOTLIN IS AVAILABLE ON… Native
40. KOTLIN IS AVAILABLE ON… Native
41. KOTLIN IS AVAILABLE ON… Native
42. KOTLIN IS AVAILABLE ON… Native
43. WHAT DOES IT MEANS?
44. WHAT DOES IT MEANS? - Can create only one project for Android and iOS
45. WHAT DOES IT MEANS? - Can create only one project for Android and iOS - Back Office can be developed in Kotlin
46. WHAT DOES IT MEANS? - Can create only one project for Android and iOS - Back Office can be developed in Kotlin - Only one language for all projects, all teams
47. VERSUS
48. SWIFT vs KOTLIN
49. JAVA vs KOTLIN
50. JAVA vs KOTLIN val person = KotlinPerson("John Doe") Null safety
51. JAVA vs KOTLIN val person: KotlinPerson = KotlinPerson("John Doe") Null safety
52. JAVA vs KOTLIN val person: KotlinPerson? = KotlinPerson("John Doe") Null safety
53. JAVA vs KOTLIN val person: KotlinPerson? = null Null safety
54. JAVA vs KOTLIN val person: KotlinPerson? = KotlinPerson("John Doe") println(person.name) // ERROR compilation Null safety
55. JAVA vs KOTLIN val person: KotlinPerson? = KotlinPerson("John Doe") println(person?.name) // print null if person is null Null safety
56. JAVA vs KOTLIN val person: KotlinPerson? = KotlinPerson("John Doe") println(person!!.name) // NPE if person is null Null safety
57. JAVA vs KOTLIN val person: KotlinPerson? = KotlinPerson("John Doe") if (person != null) println(person.name) Null safety
58. JAVA vs KOTLIN public class JavaPerson { private String name; public JavaPerson(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; JavaPerson that = (JavaPerson) o; return name != null ? name.equals(that.name) : that.name == null; } @Override public int hashCode() { return name != null ? name.hashCode() : 0; } @Override public String toString() { return "JavaPerson{name='" + name + "'}"; } } Data classes
59. JAVA vs KOTLIN data class KotlinPerson(val name: String) Data classes
60. JAVA vs KOTLIN val person = KotlinPerson("John Doe") println("Name is " + person.name) Data classes
61. JAVA vs KOTLIN val person = KotlinPerson("John Doe") println("Name is ${person.name}") Data classes
62. JAVA vs KOTLIN val person = KotlinPerson("John Doe") println("Name is $person") // Use toString function Data classes
63. JAVA vs KOTLIN fun <K, V> MutableMap<K, V>.getKey(value: V): K { return keys.first { get(it) == value } } Extensions
64. JAVA vs KOTLIN fun <K, V> MutableMap<K, V>.getKey(value: V): K { return keys.first { get(it) == value } } val key = map.getKey(value) Extensions
65. SUMMARY
66. SUMMARY - Kotlin is mature and ready for production
67. SUMMARY - Kotlin is mature and ready for production - Designed to be compatible and better than Java
68. SUMMARY - Kotlin is mature and ready for production - Designed to be compatible and better than Java - Easy to learn and high adoption by the Android community
69. SUMMARY - Kotlin is mature and ready for production - Designed to be compatible and better than Java - Easy to learn and high adoption by the Android community - Compatible with Java, Android, Javascript and soon native!
70. KOTLIN READY FOR US?
71. KOTLIN READY FOR US? - Not ready for iOS project
72. KOTLIN READY FOR US? - Not ready for iOS project - Android applications can migrate to Kotlin right now
73. KOTLIN READY FOR US? - Not ready for iOS project - Android applications can migrate to Kotlin right now - Back-Office to develop? Think to Kotlin, Ktor is there
74. NICE TO MEET YOU Gerard Paligot