Webinar about the Benefits, Timing, and Strategies for Seamless Modernization of applications with Kotlin.

1. Modernize your JAVA
applications with Kotlin:
Best Practices and Strategies
Exploring the benefits, timing and strategies for
seamless modernization of applications with Kotlin
18.07.2023
online

2. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
© kreuzwerker 2023
Agenda
2
Introduction
Why Kotlin?
When should you switch to
Kotlin?
How to make a successful
transition to Kotlin?
Conclusion and Q&A
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
| Modernise your JAVA applications with Kotlin: Best Practices and Strategies

3. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Who are we?
3
Kateryna Oliferchuk Gopal Tayal Thomas Wendzinski
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

4. kreuzwerker
We unleash digital technology.

5. 5
Founded 2012
AWS Partner since 2013
100% AWS
Berlin, Frankfurt,
Warsaw, Zurich
Migration & Modernization
Data & Analytics
Cloud Native Development
Managed Security Services
Cloud Financial Management

6. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023 6
Why Kotlin?
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

7. Released in 1995
Originally named Oak,
later renamed Java
Open-Sourced in 2006
Owned by Oracle

8. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Why JAVA?
8
Platform Stability
Wide Adoption Rate
High Performance
Backward Compatibility
Tooling & IDE Support
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

9. Released in 2011
Official Android
Language
Open-Sourced in 2012
Owned by JetBrains

10. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
A side by side comparison
10
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

11. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023 11
Kotlin Pros
Java Cons
Verbosity & Boilerplate Code Concise Syntax
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

12. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Data classes in Kotlin
12
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Lombok?
Records?

13. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Singleton objects
13
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

14. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023 14
Kotlin Pros
Java Cons
Verbosity & Boilerplate Code
No In-Built Null Safety
Concise Syntax
In-Built Null Safety
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

15. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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The ‘?’ operator
15
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
The Billion Dollar Mistake

16. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023 16
Kotlin Pros
Java Cons
Verbosity & Boilerplate Code
No In-Built Null Safety
Concurrency
Concise Syntax
In-Built Null Safety
Coroutines
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

17. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Concurrency Vs. Co-routines
17
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

18. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Modern Language Features
18
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

19. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Lambda Functions
19
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

20. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Extension Functions
20
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

21. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Kotlin DSL
21
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

22. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Interoperability with JAVA
22
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

23. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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When should you switch to
Kotlin?
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

24. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Options
24
Starting a new
project
Introducing
Midway /
Migration
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

25. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Common Challenges
25
Learning Curve
Tooling & Ecosystem
Community & Learning Resources
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

26. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Kotlin Community
26
https://discuss.kotlinlang.org/
https://dev.to/t/kotlin
https://stackoverflow.com/questions/tagged/kotlin+coroutine
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

27. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Common Challenges
27
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Learning Curve
Tooling & Ecosystem
Community & Learning Resources
Scarcity of Talents

28. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Common Advantages
28
Increased Developers Satisfaction
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

29. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Who initiates the adoption of Kotlin in teams?
29
https://www.jetbrains.com/lp/devecosystem-2022/kotlin/#who-initiates-the-adoption-of-kotlin-in-teams-
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

30. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Loved vs Dreaded
30
https://survey.stackoverflow.co/2022/#most-loved-dreaded-and-wanted-language-love-dread
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

31. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Common Advantages
31
Increased Developers Satisfaction
Improved Productivity
Boosted Codebase Maintainability
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

32. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Starting a new project
32
Clean State
Full utilization of Kotlin features
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

33. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway / Migration
33
Advantages Challenges
Gradual Adoption
Opportunity for Optimization
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Codebase Compatibility

34. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Codebase Compatibility
34
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

35. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway / Migration
35
Advantages Challenges
Gradual Adoption
Opportunity for Optimization
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Codebase Compatibility
Team Coordination
Risk of Introducing Bugs

36. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
How to successfully transition
to Kotlin?
36
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

37. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Options
37
Starting a new
project
Introducing
Midway /
Migration
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

38. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Given you are here
38
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
You are a team that already had some
adventures together
You are going to deliver a new service

39. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
39
1
Plan
Identify goals and challenges
Train
Provide resources and time
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Evolve
Try new things
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

40. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
40
1
Plan
Identify goals and challenges
1. Reflect on your
team’s capabilities
2. Extra effort to learn
a new language.
Train
Provide resources and time
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Try new things
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

41. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
41
1
Plan
Identify goals and challenges
Train
Provide resources and time
1. Provide Basic
Training.
2. Add someone with
Kotlin experience
on the team.
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Try new things
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

42. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
42
1
Plan
Identify goals and challenges
Train
Provide resources and time
2
Collaborate
Build a dev culture
1. Promote knowledge
sharing.
2. Mob/Pair
Programming
3
Start
Just do it!
4
Try new things
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

43. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
43
1
Plan
Identify goals and challenges
Train
Provide resources and time
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Try new things
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

44. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Starting a new project
44
1
Plan
Identify goals and challenges
Train
Provide resources and time
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Try new things
1. DSL for Kotlin
2. Kotlin specific
libraries and Tools
5
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

45. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Given you are here
45
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
You are a team that already had some adventures
together
You own a zoo of domains // services
You are going to create a new feature to an
existing service

46. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway/Migration
46
1
Plan
Identify goals and challenges
Train
Provide resources and time
2
Collaborate
Build a dev culture
3
Start
Just do it!
4
Try new things
5
and ..
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Evolve

47. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway
47
Have an integration plan
Address legacy code dependencies
Adapt source sets for interoperability
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

48. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway
48
Address legay code dependencies
Adapt source sets for interoperability
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Have an integration plan
Address legacy code dependencies
Adapt source sets for
interoperability

49. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway
49
Address legay code dependencies
Adapt source sets for interoperability
✅
✅
⚠
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Have an integration plan
Address legacy code dependencies
Adapt source sets for
interoperability

50. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Introducing Midway
50
Address legay code dependencies
Adapt source sets for interoperability
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Have an integration plan
Address legacy code dependencies
Adapt source sets for
interoperability

51. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Migration
51
Ensure Automated tests exist and migrate
them first
Take advantage of your IDE
Ensure tests are green
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

52. 52
Questions?

53. 53
Book a slot!
More
Questions?
https://my.meetergo.com/team/mod-webinar-follow-up/mod-webinar-follow-up-meeting

54. kreuzwerker GmbH
Ritterstr. 12
10969 Berlin
www.kreuzwerker.de
Fon +49 30 609 838 80
Fax +49 30 609 838 899
Thank you for your attention!
Your feedback is important to us!
Contact us: aws@kreuzwerker.de
https://easy-feedback.com/Modernize-You
r-Java-Applications/1696846/68G4G1

55. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Appendix
55
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

56. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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The Dark Side of Kotlin?
56
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

57. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known drawbacks
57
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Learning Curve

58. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known drawbacks
58
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Learning Curve
Build Speed & Tooling

59. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known drawbacks
59
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Learning Curve
Build Speed & Tooling
Binary Size & Runtime Overhead

60. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
60
Language Syntax
‘var’ and ‘val’ keywords
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

61. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
61
Language Syntax
‘static’ methods and fields
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

62. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
62
Language Syntax
‘equals’ method
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

63. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
63
Language Syntax
Handling Nullable Properties
converts to
maybe you want
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

64. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
64
Language Syntax
Null safety for Platform types
Better:
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

65. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
65
Language Syntax
Smart Casting
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

66. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
66
Language Syntax
Elvis Operator and friends
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

67. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
67
Language Syntax
Function Type
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

68. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
68
Language Syntax
Use Functional interfaces where possible
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

69. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
69
Language Syntax
Library / Framework Support
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

70. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
70
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Library / Framework Support
Kotlin Library - Collection Functions

71. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
71
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Library / Framework Support
Jackson Module Kotlin

72. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Source: https://github.com/sdeleuze
Known Pitfalls / Tips
72
Library / Framework Suport
https://docs.spring.io/spring-framework/reference/la
nguages/kotlin.html
spring-kotlin-functional/src/main/kotlin/f
unctional/Routes.kt at master ·
sdeleuze/spring-kotlin-functional · GitHub
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Library / Framework Support
Spring Framework

73. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
73
GitHub - mockito/mockito-kotlin: Using Mockito with Kotlin https://mockk.io/
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Library / Framework Support
Mocking

74. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Known Pitfalls / Tips
74
✅ @MockkBean for Spring also
supported
Library / Framework Support
Mocking
GitHub - mockito/mockito-kotlin: Using Mockito with Kotlin https://mockk.io/
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin

75. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
© kreuzwerker 2023
Known Pitfalls / Tips
75
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin
Library / Framework Support
KTor

76. | Modernize your JAVA applications with Kotlin: Best Practices and Strategies
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Loved vs Dreaded
76
Kotlin Java
https://survey.stackoverflow.co/2022/#most-loved-dreaded-and-wanted-language-love-dread
Exploring the benefits, timing & strategies for seamless modernization of applications with Kotlin