Modern Java for the Modern Dev

Chaitanya Munukutla — Mon, 25 May 2020 09:52:54 +0000

This is my personal experience while trying to push Java to the edge of my requirements of a Cloud-native environment. So these were the myths that are afloat about Java (or why Java is not cloud-friendly)

It is heavy
It is slow
It is not up-to-date

So here is my latest attempt to burst all those myths with a tailor made stack for any future Java micro-services I develop - OpenJDK11, Helidon MP, GraalVM, and Podman.

What is Helidon?

Helidon is a lightweight micro-service library for Java, which lets you write fast, lean, and scalable Java applications. It comes in two variants - Helidon SE, and Helidon MP. I'm not sure what the SE means, but I call it "Super-Efficient" - yes, it's ultra small, and ultra fast. But Helidon SE might not be for everyone since it's reactive-first, leverages the builder model everywhere possible. So it might be attractive to the Kotlin-fanatics.

Helidon MP however, is what steals the show. It's standards-based, and directly inherits the Jakarta EE MicroProfile specification. Though it might not seem very lucrative at first, it means that your application stands on the shoulders of the enterprise giants like Oracle WebLogic, IBM WebSphere etc. Microprofile also is vendor-agnostic. So even if you start your application with Helidon MP, you can easily migrate to IBM OpenLiberty, Payara Micro etc. It really is a commendable position taken by Oracle, IBM, Payara etc. to let developers choose the best framework for their application, instead of imposing a vendor lockdown. I assume the world does not need anymore lockdowns at this point.

Show me the code, duh

Right to it. Here is my neofetch output

And here's my Maven setup

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /maven/current
Java version: 11.0.7, vendor: Oracle Corporation, runtime: /java/11.0.7-open
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.6.14-300.fc32.x86_64", arch: "amd64", family: "unix"

Getting a quick Helidon MP project setup is as simple as shamelessly using their stock Maven archetype

mvn archetype:generate -DinteractiveMode=false \
    -DarchetypeGroupId=io.helidon.archetypes \
    -DarchetypeArtifactId=helidon-quickstart-mp \
    -DarchetypeVersion=2.0.0-M3 \
    -DgroupId=io.helidon.examples \
    -DartifactId=helidon-quickstart-mp \
    -Dpackage=io.helidon.examples.quickstart.mp

Next, it's time to jazz it up

HTTP/2 support

## Add the following line in resources/META-INF/microprofile-config.properties
server.experimental.http2.enable=true

Custom JRE image

If you've been informed of one of the awesome features included in JDK9, it's the jlink utility, which creates a custom JRE image, just enough to run your Java application (works for both JAR and WAR packages!)

mvn package -Pjlink-image

Native Java application!

Yep, not kidding. GraalVM allows you to create native Java binaries, and run them independently as shell executables.

Make sure you set your GRAALVM_HOME environment variable to the path of your GraalVM installation. Here's mine.

$ $GRAALVM_HOME/bin/java --version
openjdk 11.0.7 2020-04-14
OpenJDK Runtime Environment GraalVM CE 20.1.0 (build 11.0.7+10-jvmci-20.1-b02)
OpenJDK 64-Bit Server VM GraalVM CE 20.1.0 (build 11.0.7+10-jvmci-20.1-b02, mixed mode, sharing)

So GraalVM is your off-the-shelf JDK, plus some awesome polyglot capabilities. For the purposes of this article, I had to install the native-image extension for GraalVM

$GRAALVM_HOME/bin/gu install native-image

Next, just run Maven with the native image profile

mvn package -Pnative-image

So let me tell you how thin we made the application during this process.

The above images are all JakartaEE standard, Cloud-native and Kubernetes-ready!