Quarkus is a toolkit for Java and Kotlin development optimized for cloud environments and designed for minimal memory usage and fast startup times. It utilizes ahead-of-time (AOT) compilation to enhance performance, transforming applications into native images for GraalVM while following a closed world assumption. However, it has limitations such as unsupported dynamic class loading and limited reflection capabilities.

1. Quarkus
Supersonic Subatomic Java
By Romain Schlick
@r_schlick

2. WHAT IT IS ?

3. TOOLKIT
and
FRAMEWORK
For writing java and Kotlin applications

4. Container First
Minimal footprint Java apps optimal for running in containers
Cloud Native
Embraces 12 Factor architecture in cloud environments like Kubernetes
Microservice First
Brings lightning fast startup time and code turn around Java
Why supersonic and subatomic java ?

7. IMPERATIVE REACTIVE
Unifies
and

8. DEVELOPER JOY
• Easy to start with
• Live reload with dev mode
• Java or Kotlin
• Maven or Gradle
• Runners for Junit 4 and 5
• Isolation from GraalVM CLI/API

10. Memory / Startup time

11. HOW IT WORKS

12. TRADITIONAL APP SERVER
• JIT Compilation
• Runtime approach : hundreds of classes run only during the boot
• Later unused and occupy memory
• Ex: XML parsers, annotation lookups, management model, etc.
QUARKUS SERVER
• AoT Compilation
• Build time approach
• As much work as possible done at build time
• Build time augmentation using extensions
• Output: recorded wiring bytecode
VS

13. QUARKUS EXTENSIONS
Philosophy:
• Transform your entire app including the libraries it uses,
into an native image optimized for GraalVM
• Closed world assumption
3 Phases of Bootstrap:
• Augmentation: Produce recorded bytecode @Record(STATIC_INIT) or
@Record(RUNTIME_INIT)
• Static Init : Executed at build time in a static method on main class
• Runtime init : Executed at runtime

14. Two distinct things:
1. Graal compiler (AoT or JIT)
2. GraalVM – the polyglot VM
Supports Linux and macOS,
not windows yet

15. Polyglot programming ?

16. AoT compilation
• Static analysis
• Statically linked executable (app classes, jdk classes)
• Closed world assumption
• Dead code elimination
Enable:
• Fast process start
• Less memory
• Small size on disk

17. LIMITATIONS
« With great powers comes great cost »
• Dynamic class loading: unsupported
• JMX, JVMTI: unsupported
• Agents (jrebel, byteman, profilers): unsupported
• Java debugger: unsupported, but Native debugger (GDB) supported
• Reflection, dynamic proxies: limited

18. Ok … DEMO TIME !
STOP YOUR BULLSHIT !

19. LINKS
• http://ppalaga.github.io/presentations/190414-quarkus-
microxchng-berlin/
• https://quarkus.io/get-started/
• https://www.graalvm.org/docs/reference-manual/embed/