Micronaut is a reflection-free app-development framework that uses ahead-of-time (AoT) compilation to precompute everything in the application, paving the way for lightning-fast startup times and significantly reduced memory consumption. What if I told you that you can reduce the startup time by orders of magnitude? And what if you could reduce memory consumption even more? GraalVM is a new universal virtual machine from Oracle that supports a polyglot runtime environment. GraalVM has the ability to compile Java applications down to native machine code, making it an ideal partner for Micronaut. In this talk you will learn how you can take advantage of GraalVM's powerful capabilities to convert your Micronaut applications to run as binary native images.

1. Micronaut and GraalVM:
The power of AoT
Iván López
(@ilopmar)

2. Iván López @ilopmar
Iván López (@ilopmar)

4. Iván López @ilopmar
GraalVM
- Substrate VM: compile Java applications to native binaries
- https://www.graalvm.org

5. Iván López @ilopmar
- Reflection (with config)
- Dynamic class loading (with config)
- Dynamic proxy (with config)
- Unsafe Memory Access (partially)
- Class initializers (supported)
- InvokeDynamic bytecode and method handlers (partially)
- Lambda (supported)
- Finalizers (not supported)
- Threads (partially)
Limitations

7. Iván López @ilopmar
- Framework for microservices in the JVM
- Ultra-lightweight & reactive (Netty-based)
- Java, Groovy & Kotlin
- Ahead of Time compilation (AoT)
- No reflection, no runtime proxies
- Fast startup
- Low memory footprint
- Natively Cloud Native
- GraalVM support (improved a lot in Micronaut 2.x)
Micronaut

8. Iván López @ilopmar
$ mn create-app basic-app
--features=graalvm
Create an application with GraalVM support

9. Iván López @ilopmar
$ mn create-app basic-app
--features=graalvm
Create an application with GraalVM support
Micronaut 2.2 (Gradle & Maven)

10. Iván López @ilopmar
$ ./gradlew nativeImage
$ ./mvnw package -Dpackaging=native-image
Create native-image
$ ./gradlew dockerBuildNative
$ ./mvnw package -Dpackaging=docker-native

11. Iván López @ilopmar
- Composable native-image.properties
How does it work?

12. Iván López @ilopmar
# inject/native-image.properties
Args = --allow-incomplete-classpath
-H:EnableURLProtocols=http,https
# http/native-image.properties
Args = -H:IncludeResources=META-INF/http/mime.types
# http-netty/native-image.properties
Args = --initialize-at-run-time=
com.sun.jndi.dns.DnsClient,io.netty.handler.ssl.ConscryptAlpnSslEngine,io.netty.handler.ssl.Je
ttyNpnSslEngine,io.netty.handler.ssl.ReferenceCountedOpenSslEngine,io.netty.handler.ssl.JdkNpn
ApplicationProtocolNegotiator,io.netty.handler.ssl.ReferenceCountedOpenSslServerContext,io.net
ty.handler.ssl.ReferenceCountedOpenSslClientContext,io.netty.handler.ssl.util.BouncyCastleSelf
SignedCertGenerator,io.netty.handler.ssl.ReferenceCountedOpenSslContext,io.micronaut.buffer.ne
tty.NettyByteBufferFactory,io.netty.handler.ssl.JettyAlpnSslEngine$ClientEngine,io.netty.handl
er.ssl.JettyAlpnSslEngine$ServerEngine,io.netty.handler.codec.http2.Http2CodecUtil,io.netty.ha
ndler.codec.http2.CleartextHttp2ServerUpgradeHandler,io.netty.handler.codec.http2.Http2ServerU
pgradeCodec,io.micronaut.http.netty.channel.converters.EpollChannelOptionFactory,io.micronaut.
http.netty.channel.converters.KQueueChannelOptionFactory,io.micronaut.http.bind.binders.Contin
uationArgumentBinder$Companion,io.micronaut.http.bind.binders.ContinuationArgumentBinder
Micronaut includes everything (I)

13. Iván López @ilopmar
@AutomaticFeature
final class HibernateFeature implements Feature {
@Override
public void beforeAnalysis(BeforeAnalysisAccess access) {
// other drivers...
registerIfPresent(access, "oracle.jdbc.OracleDriver",
Oracle8iDialect.class,
Oracle9iDialect.class,
Oracle10gDialect.class,
Oracle12cDialect.class);
}
}
Micronaut includes everything (II)

14. Iván López @ilopmar
private void handleOracle(BeforeAnalysisAccess access) {
Class<?> oracleDriver = access.findClassByName(ORACLE_DRIVER);
if (oracleDriver != null) {
registerAllIfPresent(access, "oracle.jdbc.driver.T4CDriverExtension");
registerAllIfPresent(access, "oracle.jdbc.driver.T2CDriverExtension");
registerAllIfPresent(access, "oracle.net.ano.Ano");
registerAllIfPresent(access, "oracle.net.ano.AuthenticationService");
registerAllIfPresent(access, "oracle.net.ano.DataIntegrityService");
registerAllIfPresent(access, "oracle.net.ano.EncryptionService");
registerAllIfPresent(access, "oracle.net.ano.SupervisorService");
ResourcesRegistry resourcesRegistry = getResourceRegistry();
if (resourcesRegistry != null) {
resourcesRegistry.addResources("META-INF/services/java.sql.Driver");
resourcesRegistry.addResources("oracle/sql/converter_xcharset/lx20002.glb");
resourcesRegistry.addResources("oracle/sql/converter_xcharset/lx2001f.glb");
resourcesRegistry.addResources("oracle/sql/converter_xcharset/lx200b2.glb");
resourcesRegistry.addResourceBundles("oracle.net.jdbc.nl.mesg.NLSR");
resourcesRegistry.addResourceBundles("oracle.net.mesg.Message");
}
initializeAtBuildTime(access,
"oracle.net.jdbc.nl.mesg.NLSR_en",
"oracle.jdbc.driver.DynamicByteArray",
"oracle.sql.ConverterArchive",
"oracle.sql.converter.CharacterConverterJDBC",
"oracle.sql.converter.CharacterConverter1Byte"
);
initializeAtRuntime(access, "java.sql.DriverManager");
}
}
Micronaut includes everything (III)

15. Iván López @ilopmar
Micronaut includes everything (IV)

16. Iván López @ilopmar
Micronaut includes everything (V)

17. Iván López @ilopmar
- @Introspected
- @TypeHint
- @ReflectiveAccess
- GraalTypeElementVisitor
-reflect-config.json
-resource-config.json (* Micronaut 2.0)
Support in Micronaut

18. DEMO

19. Iván López @ilopmar
Demo

20. Iván López @ilopmar
14 vs 140 MB
What about memory?

21. Iván López @ilopmar
- Create a native image takes a lot of time
- And it needs a lot of RAM
- GraalVM changes so fast (and they break things)...
- ...and so we do ;-)
- We used Travis for testing Micronaut (now Github Actions), but...
- ...Travis has a limit for RAM
- We needed another way...
So… how do we test this?

23. Iván López @ilopmar
- Scheduled jobs every hour (2.2.x / 2.3.x)
- Only run if new commits in Micronaut or GraalVM
- Compile GraalVM from source code (JDK8 & JDK 11)
- Also test GraalVM stable
- Create native images for test Micronaut applications
- Run native images and execute functional tests
- https://github.com/micronaut-graal-tests
- https://gitlab.com/micronaut-projects/micronaut-graal-tests
Tests using Gitlab CI

24. Iván López @ilopmar
- Basic application: DI, POJO serialization, reactive types, HTTP Client
- Cache
- Micronaut function
- Service discovery: Consul & Eureka
- Static resources & views: Handlebars, Thymeleaf, Freemarker, Velocity, Pebble
- Management & Metrics endpoints
- Distributed tracing: Zipkin
- RabbitMQ: Fire-and-forget & RPC
- MQTT
Test applications Micronaut-GraalVM

25. Iván López @ilopmar
- Security: JWT, Basic Auth, Cookie, Session
- Scheduled jobs
- Micronaut Data JDBC: H2, Postgresql, Oracle, MariaDB, MS SQL Server
- Micronaut Data JPA-Hibernate: H2, Postgresql, MariaDB
- Bean Introspection
- Servlet: Tomcat & Jetty
- Flyway & Liquibase
- AWS app & function
- gRPC
Test applications Micronaut-GraalVM

26. Iván López @ilopmar
Gitlab CI

27. Iván López @ilopmar
Gitlab CI

28. Iván López @ilopmar
Gitlab CI 2 years ago

29. Iván López @ilopmar
x8
- JDK 8 & 11
- 2.3.x & 2.2.x
- GraalVM dev/stable
Gitlab CI today

30. Iván López @ilopmar
Gitlab CI

31. Iván López @ilopmar
Use cases

32. Iván López @ilopmar
- https://launch.micronaut.io (Google Cloud)
- Micronaut CLI: Linux, MacOS, Windows
- AWS Lambda + Custom runtime
Use cases

33. Iván López @ilopmar
GraalVM is a new and
interesting technology
Micronaut AoT is the
perfect match
Out-of-the-box support
in Micronaut
New improvements in
every release
Fast startup & low
memory footprint
Developers happy and
productive
Summary

34. Thank you!
@ilopmar
lopez.ivan@gmail.com
https://github.com/ilopmar
Iván López
https://bit.ly/jlove-micronaut
Questions?