Running a Spring Boot application but still want to benefit from Quarkus and its supersonic, subatomic Java capabilities? Me too! With a “hello world” everything looks simple, but what about a real app? Will it be easy? Or fun? In this session we’ll show our experience migrating a Spring Boot app to Quarkus. Technologies involved in the app include Hibernate, Prometheus, REST endpoints, and more. Be prepared to listen to a journey of reality, failure, and wins in the Quarkus universe.

1. Migrating
QUARKUS

2. Contents
1. who am i
2. what can you expect
3. what is quarkus
4. why migrate
5. migration
a. application description
b. steps
6. performance comparative
7. references

3. $ whoami
JUG organiser at BarcelonaJUG
Cofounder of JBCNConf ( Barcelona )
Software Engineer at Red Hat
App. Modernisation and Migration team
@vilojona
jvilalop@redhat.com
aytartana.wordpress.com
github.com/jonathanvila

4. What can you expect ?
My experience
v 2.2.5
v 1.7.0
opinionated option
magistral lecture
something that works
THE way
QUARKUS

5. Quarkus brief description

6. What is Quarkus ?
A Kubernetes Native, Java, Scala, Kotlin stack
tailored for GraalVM and OpenJDK HotSpot
crafted from the best of breed Java libraries and standards.

7. 300x faster 10x smaller focused on easy to code
opensource fast paced releases tons of extensions
Quarkus key facts

8. Quarkus extensions ( > 90 )
Kafka
Camel
Keycloak
Spring
Vert.x
RestEasy
….
Microprofile
Openshift
Jaegger
Flyway
Hibernate
Infinispan
...

9. Quarkus evolution
2018-12 v 0.0.1
2019-06 v 0.15.0
2019-11 v 1.0.0 Release
2020-01 v 1.2.0
1 minor version every 2 weeks !!! (+/-)

10. Quarkus performance

11. Quarkus OSS status

12. Migration

13. Why to migrate
My experience
easy to develop with an easy CDI, REST, …
long startup times, eternal tests
heavyweight
too many things happen under the hood
easy to develop applications
fast
lightweight
GraalVM compatible
QUARKUS
✅ FaaS compatible ( lambdas )
✅ less money on public cloud

14. Application migrated
Spring Data ( repositories, jdbc , ... )
Spring Web ( REST )
Spring Security
Spring documentation ( Swagger )
Spring actuators
Spring micrometer
Spring CDI
Spring AOP
Spring cache
Hibernate Panache
JaxRS
Quarkus Security
OpenAPI
SmallRye Health
Microprofile Metrics
CDI Spec ( Arc )
---
Quarkus cache ( Caffeine )
QUARKUS

15. Elements not migrated
Spring JDBC querying
* no helper methods to work with Inserts, Updates….
* no equivalent to org.springframework.jdbc.core classes
* we need to reimplement everything using AGROAL
JMX
* not supported by GraalVM definition

16. CDI
● Replace Autowired by Inject
● Beans declaration using @ApplicationScoped
● Auto injection on Constructors
● Lazy by default

17. CDI
PROs
● straight forward migration for Beans
● no feature missing
CONs
● no annotation built-in beans
injection depending on Profile
● no private members on injection

18. JPA Repositories
● Repository classes to implement PanacheRepositoryBase<T, Integer>
Quarkus will generate the implementation of the usual methods :
list , find, persist, delete

19. JPA Repositories
PROs
● straightforward migration
CONs
● no Query DSL methods

20. Spring REST to JAX-RS
● Move from Spring REST to the standard JAX-RS
@RestController
@RequestMapping, @GetMapping,
@PostMapping, @PutMapping,
@DeleteMapping
@PathVariable
@Path
@GET,
@POST, @PUT
@DELETE
@PathParam
QUARKUS

21. Spring REST to JAX-RS
PROs
● straightforward migration
INFO
● Spring also supports JAX-RS as 3rd party lib

22. Spring REST Security to Quarkus Security
● replaced Spring REST Security

23. Spring REST JDBC Security to Elytron JDBC realm
Add extension dependency : elytron-security-jdbc
Configure on properties file and remove configureGlobal method

24. Spring REST Security to Quarkus security
PROs
● Almost the same result
● By configuration rather than code
CONs
● Quarkus doesn’t have an expression language

25. CORS
● configured CORS in the application.properties file

26. CORS
PROs
● easy to enable , no code involved
CONs
● at global level, not per Controller

27. Metrics
● Add smallRye metrics extension
● Annotate each method ( for custom metrics )

28. Metrics
PROs
● OpenMetrics standard naming
CONs
● different naming than micrometer
( compatibility toggle being developed )
● not the same metrics
● no AOP so you need to annotate every
method

29. Validation
● Spring Validation to Hibernate Validator
● Move from @ControllerAdvice to JAX-RS ExceptionMapper

30. Validation
PROs
● standard
● easy
CONs
● none

31. Swagger ( OpenAPI v 3.0 )
● Add extension “openapi”
● extend Application

32. Swagger ( OpenAPI v 3.0 )
PROs
● straightforward migration
● standard and easy way to configure
● Swagger-UI OOTB
CONs
● not REST paths scan configuration

33. AOP for app metrics
● use of microprofile metrics annotations

34. AOP for repository metrics
● using Hibernate built in metrics enabled in properties

35. AOP for app metrics
PROs
● standard
● easy to customise
CONs
● need to annotate ALL methods one by one for
custom app metrics
● no expression language to define methods affected

36. Local caching
● Spring uses a default ConcurrentHashMap
● Caffeine uses a ConcurrentLinkedHashMap
● Add “cache” extension ( Caffeine ) and annotate the method

37. Local Caching
PROs
● easy to implement and configure
● straightforward migration
CONs
● none

38. Test : REST
MockMVC -> RestAssured

39. Test REST
PROs
● RESTassured is easy to handle and very intuitive
CONs
● No way to simulate Roles without creating an user for each role to test
INFO
● Changed JSonPath to GPath

40. Test - resources
● Annotate test suites with @QuarkusTest to boot the app
● Annotate test suites with @QuarkusTestResource to load an embedded
resource

41. Test - Mock
● Use the quarkus-mockito dependency : quarkus-junit5-mockito
● Annotate mocks with @InjectMock

42. Spring API in Quarkus

43. Spring WEB ( REST) : spring-web extension
Using same Spring API for REST Supported Annotations
@RestController
@RequestMapping
@GetMapping
@PostMapping
@PutMapping
@DeleteMapping
@PatchMapping
@RequestParam
@RequestHeader
@MatrixVariable
@PathVariable
@CookieValue
@RequestBody
@ResponseStatus
@ExceptionHandler

44. Spring DI : spring-di extension
Using same API as Spring DI
Annotations Supported
@Autowired @Repository
@Qualifier @Scope
@Value @Component
* doesn’t support an expression language
@Configuration @Service
@Bean

45. Spring Data : spring-data-jpa
Using same API for Spring Data Supported
Any interface of : Repository,
CrudRepository, PagingAndSortingRepository,
JpaRepository
Derived Query Methods
User defined Queries
Not Supported
Invocations to any method of
QueryByExampleExecutor
QueryDSL

46. Spring Security: spring-security extension
Using same API as Spring Security
Annotations Supported
@Secured
@Preauthorized
Expressions allowed
hasAnyRole
permitAll
denyAll
isAnonymous
isAuthenticated
#paramName ==

47. Performance comparative (shallow)
SPRING BOOT
2.2.5
QUARKUS
Hotspot 1.8
QUARKUS
GraalVM 20.1
build
( uber-jar )
4.3 s
48 Mb
13 s
42 Mb
185 s
97 Mb
boot 6.8 s
630 Mb
2.6 s ( 3x )
251 Mb ( 2.5x )
0.462 s ( 15x )
21 Mb ( 30x )

48. References

49. Repositories
● Spring REST PetClinic
https://github.com/spring-petclinic/spring-petclinic-rest
● Quarkus REST PetClinic
https://github.com/jonathanvila/spring-petclinic-rest/tree/quarkus
Documentation/News/Help
● https://quarkus.io
● @QuarkusIO
● https://developers.redhat.com/search/?t=quarkus
● quarkus-dev@googlegroups.com

50. Interactive Tutorials ( Katacoda )
● https://developers.redhat.com/courses/quarkus/
List of Tutorials
● Getting Started
● For Spring Devs
● Streaming with
Kafka
● Hibernate and
Panache
● Prometeus &
Grafana

51. Cheat Sheet
● https://lordofthejars.github.io/quarkus-cheat-sheet/
by Alex Soto

52. Do you want to start coding with Quarkus ?
https://code.quarkus.io/

53. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
Red Hat MTA (Migration Toolkit for Applications)

54. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
Red Hat MTA (Migration Toolkit for Applications)

55. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
Red Hat MTA (Migration Toolkit for Applications)

56. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
○ Plugin for Eclipse (Che), VSCode
Red Hat MTA (Migration Toolkit for Applications)

57. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
Red Hat MTA (Migration Toolkit for Applications)

58. ● Rules to help to migrate from SB to Quarkus ( MTA 5.0 )
○ Opensource tool to help on applications migrations
■ https://developers.redhat.com/products/mta/overview
■ https://github.com/windup
○ 26 rules , covering
■ DI
■ Integration
■ Metrics
■ JPA
■ Security
■ Web
■ Shell
■ ….
○ Plugin for Eclipse (Che), VSCode
Red Hat MTA (Migration Toolkit for Applications)

59. Real use cases
Lufthansa Technik AVIATAR experiences significant cloud resources
savings by moving to Kubernetes-native Quarkus (link)
Suomen Asiakastieto Oy chooses Quarkus for their microservices
development (link)
Vodafone Greece replaces Spring Boot with Quarkus (link)
● “Quarkus offers by default (without trying to optimize it) is 50%-60% more
lightweight (in JVM mode) that what Spring offers”
● “30 to 40% better developer productivity vis-a-vis Spring Boot,”
Public Clouds exp.
-- Internal Labs ---
Save up to :
● 37 % on Cloud ( Quarkus JVM )
● 71 % on Cloud ( Quarkus + GraalVM )

60. Books ( devs not only consume tech )
Sci FyMindNovel

61. @vilojona
jvilalop@redhat.com
aytartana.wordpress.com
github.com/jonathanvila
Thank you :)