Supersonic Subatomic Java

Peter Palaga

Agenda

An 8 ms demo
What is Quarkus
How it works
More Quarkus

Demo

$ which docker # make sure you have docker
~/bin/docker
$ mvn clean package -Pnative -Dnative-image.docker-build
$ ls -lh target/*-runner
-rwxrwxr-x. 1 ppalaga ppalaga 19M Mar 20 14:39 target/quarkus-hello
$ ./target/*-runner
INFO  [io.quarkus] (main) Quarkus 0.22.0 started in 0.004s.
INFO  [io.quarkus] (main) Installed features: [cdi, resteasy]

https://quarkus.io/guides/building-native-image-guide

What is Quarkus

Toolkit

and

Framework

for writing Java, Kotlin and Scala applications

Embracing existing standards

Java EE			Spring
Servlet JAX-RS JPA, JDBC CDI Bean Validation Transactions	Fault Tolerance Health JWT Metrics (Prometheus)	OpenAPI OpenTracing (Jaeger) Reactive Messaging (Kafka, AMQP, MQTT) Rest Client	Spring DI¹ Spring Web¹ Spring Data¹ ¹⁾ via compatibility layers

Well established

Libs and frameworks

Eclipse Vert.x	Netty	Apache Camel	Infinispan	Caffeine	Keycloak
Kubernetes	AWS Lambda	Azure Functions	Apache Tika	ElasticSearch	Kogito

Databases

MySQL, MariaDB
PostgreSQL
MS SQL Server
H2

FlyWay
Amazon DynamoDB‎
MongoDB
Neo4j

Unifies

Imperative

and

Reactive

@Inject
SayService say;

@GET
@Produces(MediaType.TEXT_PLAIN)
public String hello() {
    return say.hello();
}

@Inject @Stream("kafka")
Publisher<String> reactiveSay;

@GET
@Produces(MediaType.SERVER_SENT_EVENTS)
public Publisher<String> stream() {
    return reactiveSay;
}

Developer joy

Easy to start with:
mvn quarkus:create or code.quarkus.io
Live reload:
mvn compile quarkus:dev
Java, Kotlin or Scala
Maven or Gradle
Runners for JUnit 5
Isolation from GraalVM CLI/API

Container First

💾

Small size on disk

✓

Small container images

Fast boot time

Instant scale up

Low memory footprint

More containers with the same RAM

Measuring memory

RSS¹ = all RAM consumed by the process

$ ps -o pid,rss,command -p $(pgrep quarkus)
  PID   RSS COMMAND
11229 12628 ./target/quarkus-hello

¹⁾ Resident Set Size

Memory (RSS)

	Quarkus + GraalVM	Quarkus + OpenJDK	Traditional Cloud-Native Stack
REST	13 MB	74 MB	140 MB
REST+JPA	35 MB	130 MB	218 MB

Startup time

Modern frameworks use lazy initialization

"started" before all classes are initialzed

What matters:

Time to first request

Time to first request^1/2

@Path("/")
public class GreetingEndpoint {
    @GET @Path("/greeting")
    public String greeting(@QueryParam("name") String name) {
        System.out.println(System.currentTimeMillis());
        return "Hello " + name;
    }
}

Time to first request^2/2

$ while [[ \
    "$(curl -s -o /dev/null -w '%{http_code}' localhost:8080/hello)" \
       != "200" \
  ]]; do sleep .00001; done

$ echo $(($(date +%s%N)/1000000)) && target/*-runner
1552931436155
INFO  [io.quarkus] (main) Quarkus 0.22.0 started in 0.035s.
INFO  [io.quarkus] (main) Installed features: [cdi, resteasy, resteasy-jsonb]
1552931436637

$ expr 1552931436637 - 1552931436155
482      # Time to first request in milliseconds

Time to first request

REST

REST + JPA

How it works

Traditional app server

Hundreds of classes run only during the boot
Later unused
Still occupy memory

XML parsers, annotation lookups, management model, ...

Quarkus:

Build time boot

As much work as possible done at build time

Output: recorded wiring bytecode

An example:

Build time CDI (1/2)

An example:

Build time CDI (2/2)

// User beans
@ApplicationScoped
class Catalog {

  @Inject
  Pricing pricing;

  @PostConstruct
  void init() {}
}



@ApplicationScoped
class Pricing { ... }

// Metadata (generated as bytecode)
class Catalog_Bean {

  Pricing_Bean pricingBean;

  Catalog create() {
    Catalog catalog = new Catalog();
    catalog.pricing =
               pricingBean.create();
    catalog.init();
    return catalog;
  }
}

class Pricing_Bean {...}

// The "main" class
// In reality generated as bytecode, here strongly simplified
class Application {
  static Map<String, Bean> beans = new ...Map();
  static Map<String, Supplier<Object>> appContext = new ...Map();
  static {
    // Wire the beans
    Pricing_Bean pricingBean = new Pricing_Bean();
    beans.put(Pricing_Bean.key, pricingBean);
    Catalog_Bean catalogBean = new Catalog_Bean();
    catalogBean.pricingBean = pricingBean;
    beans.put(Catalog_Bean.key, catalogBean);

    // Some beans can even be instantiated already
    Pricing pricing = pricingBean.create();
    appContext.put(Pricing_Bean.key, () -> pricing)
    Catalog catalog = catalogBean.create();
    appContext.put(Catalog_Bean.key, () -> catalog)
  }}

Wiring code invocation

Decided by extensions

`static` initializer	OR	`main()`
preferred	OR	access to files, sockets, etc.

Build oriented container

Quarkus extensions

Units of Quarkus distribution (your Maven deps)
They configure, boot and integrate a lib/framework into a Quarkus application
Make the code lighter to run on a JVM
Make the code fit for the GraalVM

Quarkus Extensions ecosystem

New extensions are welcome!
Follow the guide for extension authors
Can be developed externally → Camel Quarkus
Soon: 3rd party extensions on code.quarkus.io and in the Quarkus universe BoM

Two distinct things:

Graal compiler (AoT or JIT)
GraalVM - the polyglot VM

^{In this presentation:}

GraalVM

Graal compiler

SubstrateVM

AoT¹ compilation with GraalVM

¹⁾ Ahead-of-time (1/3)

AoT compilation with GraalVM

(2/3)

Static analysis
Closed world assumption
Dead code elimination:
classes, fields, methods, branches

AoT compilation with GraalVM

(3/3)

$ native-image -jar my-app.jar
$ ./my-app

Limitations

Response latency

No JIT (just in time) compilation on SubstrateVM
Stock JVMs:
- Slower to boot, need more RAM
- But faster to serve after warmup
Measure your use case

Efficiency through density

in cloud environments

Dynaminc Classloading

Deloying jars, wars, etc. at runtime impossible

JVMTI, JMX

+ other native VM interfaces

No agents

JRebel, Byteman, profilers, tracers, ...

JVMTI, JMX

+ other native VM interfaces

No Java debugger
Native debugger (GDB) still works
DWARF debug symbols
- Inserted only by GraalVM enterprise
- Allows stepping through your java code

Miscellaneous

Security Manager

finalize() (deprecated anyway)

InvokeDynamic and MethodHandles

Reflection

Requires registration via native-image CLI/API

@RegisterForReflection in Qarkus

Require registration via native-image CLI/API

Dynamic proxies
Resources
JNI, Unsafe Memory Access, ...

Static init

1/2

Build time OpenJDK instance:

Resolve classes, run "safe" static initilizers
Take a snapshot of the produced heap
Store it in the executable

Static init

2/2

Downsides:

no file handles, sockets, threads

What Quarkus shields you from

$ native-image -jar my-app.jar \
    -H:InitialCollectionPolicy=com.oracle.svm.core.genscavenge.CollectionPolicy$BySpaceAndTime \
    -J-Djava.util.concurrent.ForkJoinPool.common.parallelism=1 \
    -H:FallbackThreshold=0 \
    -H:ReflectionConfigurationFiles=...
    -H:+ReportExceptionStackTraces \
    -H:+PrintAnalysisCallTree \
    -H:-AddAllCharsets \
    -H:EnableURLProtocols=http \
    -H:-JNI \
    -H:-UseServiceLoaderFeature \
    -H:+StackTrace \
    --no-server \
    --initialize-at-build-time=... \
    -J-Djava.util.logging.manager=org.jboss.logmanager.LogManager \
    -J-Dio.netty.leakDetection.level=DISABLED \
    -J-Dvertx.logger-delegate-factory-class-name=io.quarkus.vertx.core.runtime.VertxLogDelegateFactory \
    -J-Dsun.nio.ch.maxUpdateArraySize=100 \
    -J-Dio.netty.allocator.maxOrder=1 \
    -J-Dvertx.disableDnsResolver=true

More Quarkus!

Native

Either have docker (easier)
Or export GRAALVM_HOME=...

$ mvn clean package -Dnative -Dnative-image.docker-build
$ ls -lh target/*-runner
-rwxrwxr-x. 1 ppalaga ppalaga 19M Mar 20 14:39 target/quarkus-hello
$ ./target/*-runner
INFO  [io.quarkus] (main) Quarkus 0.22.0 started in 0.005s.
INFO  [io.quarkus] (main) Installed features: [cdi, resteasy]

https://quarkus.io/guides/building-native-image-guide

Discover extensions

$ mvn quarkus:list-extensions
...
[INFO] Available extensions:
...
[INFO]   * Hibernate ORM (io.quarkus:quarkus-hibernate-orm)
[INFO]   * Hibernate ORM with Panache (io.quarkus:quarkus-hibernate-orm-panache)
[INFO]   * Hibernate Validator (io.quarkus:quarkus-hibernate-validator)
...

https://quarkus.io/guides/maven-tooling.html

Add an extension

$ mvn quarkus:add-extension -Dextensions=hibernate-orm-panache

https://quarkus.io/guides/maven-tooling.html

Panache

Makes simple Hibernate ORM easy

@Entity
public class Person extends PanacheEntity {
    public String name;
    public LocalDate birth;
    public PersonStatus status;
}

https://quarkus.io/guides/hibernate-orm-panache-guide

Panache persist

// Create a person
Person person = new Person();
person.name = "Stef";
person.birth = LocalDate.of(1910, Month.FEBRUARY, 1);
person.status = Status.Alive;

// Persist and delete
person.persist();
if (person.isPersistent()){
  person.delete();
}

https://quarkus.io/guides/hibernate-orm-panache-guide

Panache Queries

List<Person> allPersons = Person.listAll(); // All persons
Person p = Person.findById(personId); // Specific person by ID
// Living persons
List<Person> livingPersons = Person.list("status", Status.Alive);

// Count
int countAll = Person.count();
int countAlive = Person.count("status", Status.Alive);

// Delete
Person.delete("status", Status.Alive);
Person.deleteAll();

https://quarkus.io/guides/hibernate-orm-panache-guide

More Panache

Paging
Sorting
Simplified query language
Autogenerated DAO/Repositories

https://quarkus.io/guides/hibernate-orm-panache-guide

Quarkus wrap up

Good old Java
Good old standards and libs
Efficiency level of Go language

Makes Java the choice #1 for the cloud and serverless

Quarkus Links

Docs & guides: https://quarkus.io/
Quickstarts: github/quarkusio/quarkus-quickstarts
Stack Overflow tag: quarkus

Peter Palaga

Agenda

Demo

Demo

What is Quarkus

Toolkit

Framework

Embracing existing standards

Libs and frameworks

Databases

Imperative

Reactive

Developer joy

Container First

Measuring memory

Memory (RSS)

Startup time

Time to first request

Time to first request1/2

Time to first request2/2

Time to first request

How it works

Traditional app server

Build time boot

Build time CDI (1/2)

Build time CDI (2/2)

Wiring code invocation

Build oriented container

Quarkus extensions

Quarkus Extensions ecosystem

GraalVM

Graal compiler

SubstrateVM

AoT1 compilation with GraalVM

AoT compilation with GraalVM

AoT compilation with GraalVM

Limitations

Response latency

Efficiency through density

Dynaminc Classloading

JVMTI, JMX

JVMTI, JMX

Miscellaneous

Reflection

More

Static init

Static init

What Quarkus shields you from

More Quarkus!

Native

Discover extensions

Add an extension

Panache

Panache persist

Panache Queries

More Panache

Quarkus wrap up

Quarkus Links

Time to first request^1/2

Time to first request^2/2

AoT¹ compilation with GraalVM