ITT 2017 - Maciek Próchniak - OSGi, Java 9? do we still need modularity in the world of microservices

Maciek Próchniak talks about Microservices. Microservices architecture is one of the most trendy topics in IT these days. Everyone looks at Netflix, LinkedIn or Zalando and tries to be like them.
It’s all very good. But at heart of this revolution lie some well known ideas on modularity and decoupling.
And guess what? Idea of modular Java applications is also not new. Even term “microservice” has been in use on JVM since many, many years. However, the main technology for modular Java - OSGi - was always struggling to gain proper attention and we’re still waiting for modules in JDK itself.
In this talk, Maciek Próchniak explains why you shouldn’t too easily dismiss both OSGi and Java 9 - in many use cases, with little effort they can give you important benefits, without having to spin hundreds of VMs or containers.

Transcript

1. Java 9/OSGi?
   Microservices?
   

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2. Maciek Próchniak
   

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3. Timeline
   

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4. Meanwhile...
   

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5. FFW 2017
   

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6. Bootiful future?
   

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7. Bootiful future?
   

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8. But...
   

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9. How tall are you?
   

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10. Case 1 - startup
    

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11. Case 2 - frameworks?
    

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12. Case 3 - Enterprise
    

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13. Case 3 - Enterprise
    

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14. What are microservices
    for?
    

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15. Decoupling
    

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16. Decoupling
    

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17. Coupling
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18. Code level
    

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19. Deployment level
    

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20. Runtime coupling?
    

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21. Stop in between?
    

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22. Stop in between?
    

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23. Stop in between?
    

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24. JVM?
    

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25. Java modules
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28. Jigsaw...
    

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32. Leave prejudice
    … for next 30min
    

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34. Module
    

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35. Module
    

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36. Export/Import
    module mproch.services.order {
    requires mproch.services.user;
    exports pl.mproch.services.order.api;
    }
    Export-Package: pl.mproch.services.order.api;
    uses:="javax.ws.rs,javax.ws.rs.core";version="1.0.0"
    Import-Package: javax.ws.rs;version="[2.0,3)"
    

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37. What should be module?
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38. API vs Library vs Service
    

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39. API vs Library vs Service
    

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40. API vs Library vs Service
    

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41. Deployment?
    

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42. Deployment?
    

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43. Versioning?
    

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44. Semantic versioning
    

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46. OSGi?
    Error executing command: Error restarting bundles: Unable to start bundle 278: Uses constraint
    violation. Unable to resolve resource demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)]
    because it is exposed to package 'javax.persistence' from resources javax.persistence
    [javax.persistence [248](R 248.0)] and org.apache.geronimo.specs.geronimo-jpa_2.0_spec
    [org.apache.geronimo.specs.geronimo-jpa_2.0_spec [266](R 266.0)] via two dependency chains. Chain
    1: demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)] import:
    (&(osgi.wiring.package=javax.persistence)(version>=2.1.0)) | export: osgi.wiring.package:
    javax.persistence javax.persistence [javax.persistence [248](R 248.0)] Chain 2:
    demo-persistence-jpa [demo-persistence-jpa [278](R 278.0)] import:
    (osgi.wiring.package=org.hibernate.proxy) | export: osgi.wiring.package=org.hibernate.proxy;
    uses:=javax.persistence com.springsource.org.hibernate [com.springsource.org.hibernate [230](R
    230.0)] import: (&(osgi.wiring.package=javax.persistence)(version>=1.0.0)(!(version>=2.0.0))) |
    export: osgi.wiring.package: javax.persistence org.apache.geronimo.specs.geronimo-jpa_2.0_spec
    [org.apache.geronimo.specs.geronimo-jpa_2.0_spec [266](R 266.0)] Unresolved requirements:
    [[demo-persistence-jpa [278](R 278.0)] osgi.wiring.package;
    (osgi.wiring.package=org.hibernate.proxy)]
    

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47. Java 9?
    

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48. Versioning is HARD...
    

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49. Modules over microservices
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50. Service is not only code
    

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51. Service = Code + Behaviour
    

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52. Behaviour
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53. Spring/CDI?
    @Singleton
    public class UserService {
    @Value(“#{user.maxAge}”)
    private int maxAge;
    @PostConstruct
    public void init() {
    }
    }
    

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54. Java 9?
    module UserModule {
    provides pl.mp.user.api.UserService with pl.mp.user.impl.DbUserService;
    }
    module OrderModule {
    requires UserModule;
    uses pl.mp.user.api.UserService;
    }
    ServiceLoader services = ServiceLoader.load(UserService.class);
    services.iterator()
    

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56. DI - Service Registry
    (name=”userService”)
    name=”userService”
    

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57. Context separation
    @Singleton
    @OsgiServiceProvider
    public class UserService {
    }
    public class OrderService {
    @OsgiService
    @Inject
    UserService userService
    }
    

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58. Context separation
    

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59. DOSGi
    

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60. Lifecycle?
    @Singleton
    public class UserService {
    @PostConstruct
    public void init() {
    }
    }
    @Component
    public class UserService {
    @Activated
    @Updated
    public void init() {
    }
    }
    

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61. Dynamic updates?
    

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62. Thread::kill
    

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63. Services over microservices
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64. But does it have Spring
    Boot??
    

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65. But does it have Spring Boot??
    

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66. ‘Enterprise’ features
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68. Declarative profiles
    

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69. Profiles deployment
    

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70. DEMO
    

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71. But does it have Spring Boot??
    

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72. OSGi + Karaf platform
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74. Does it work in
    production?
    

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75. Our case
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76. Our case
    

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77. Do we still need modularity?
    

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78. What do you need?
    

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79. What do you need?
    

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80. What do you need?
    

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82. Thanks
    

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