The new GraalVM from Oracle supports multiple language including JavaScript, Python, Ruby, R, C++ as well as Java and other JVM languages. This opens up interesting possibilities for polygot enterprise applications. Now you can use a Node library in a Java application or call an R statistical function from an EJB. Previously, this type of integration was extremely challenging. This session will provide recipes to get up and running along with best practices and some cool demos. Code: https://github.com/rcuprak/graalvm_jee

1. POLYGOT JAVA EE ON
THE GRAALVM
Ryan Cuprak

2. What is GraalVM?
• OpenJDK distribution from Oracle
• Java 8 update 212
• Oracle technologies not included (Java Webstart etc.)
• Community & Enterprise Editions
• Enables polygot development:
• JavaScript, Python, R, Ruby, C, C++
• Can generate native, statically linked executables

3. OpenJDK Distributions
Confused about distributions?

4. OpenJDK Distributions
GraalVM vs. other OpenJDK distributions:
• Additional languages (JavaScript, R, Python, Ruby etc.)
• Different JIT compiler (better performance)
• Can generate native images
• Isolates – multiple VM instances in process

5. Why GraalVM?
• Interop with other languages painful/high impact:
• JNI
• Process API painful
• Nashorn can’t keep up…
• Java can’t compete in serverless
• Startup time to long
• Image size too big
GraalVM native-image
Generates statically
linked native executable

6. GraalVM Overview
Source: https://www.graalvm.org/docs/

7. GraalVM Components
GraalVM Compiler Just-in-Time (JIT) compiler
implemented in Java (like C2 in
hotspot)
GraalVM Native Image Ahead-of-time compilation technology
that produces executable binaries of
class files.
Truffle Framework Framework for implementing
languages on top of GraalVM
Instrumentation Support Language-agnostic debugger, profiler,
heap viewer tool chain

8. GraalVM Pieces
• Substrate VM – Ahead-of-Time Compiler, turns a regular
Java application into a binary file
• https://github.com/oracle/graal/blob/master/substratevm/README.
md
• Sulong – high-performance LLVM bitcode interpreter built
on the GraalVM.
• https://github.com/oracle/graal/tree/master/sulong

9. GraalVM Pieces
• Java Hotspot VM + GraalVM compiler
• Node.js runtime + GraalVM JavaScript interpreterRuntimes
• GraalVM compiler
• JavaScript interpreter
• LLVM bytecode interpreter
• GraalVM Polygot API
Libraries
• JavaScript REPL
• LLVM bitcode interpreter
• GraalVM Updater
Utilities

10. GraalVM

11. Available Libraries
0 100000 200000 300000 400000 500000 600000 700000 800000
Java
Ruby
R
Python
Node
Non-Java
• Java packages 30%
• C/C++ Libraries not included!

12. Top Libraries

13. Why Polygot?
- Use best tool for the job -

14. GraalVM FAQ
• Can’t Java already run JavaScript, Python, Ruby via
Nashorn/Rhino, Jython, and Ruby?
• Was Nashorn killed because of GraalVM?
• Native libraries, what’s wrong with JNI?
• Is native-client related to jlink?
Yes – but with lots of limitations…
Very challenging…
- No -
- No -

15. GraalVM FAQ…
• With GraalVM can I leverage native libraries etc.?
• Does it require a commercial license for production?
• What platforms are supported?
• Do existing Java/Jakarta EE containers run on GraalVM?
- Yes -
- No -
- Mac / Linux -
- Yes -

16. GraalVM Possibilities
Invoke
Invoke
Invoke
Invoke
Invoke
Invoke

17. GraalVM Possibilities…
Invoke Invoke
Invoke Invoke
Invoke Invoke

18. GraalVM + Jakarta EE
• Polygot expands JEE ecosystem possibilities
• Unifies enterprise architecture
• No separate processes for python/Javascript
• Use same libraries server-side/client-side
• Example: Run same UI validation logic on server as client.
• No clunky language interop packages
• Improves performance (R/Ruby/Java)
• Simplifies runtime architecture and coordination

19. JEE + GraalVM
Wrap
Invoke

20. Installation https://www.graalvm.org/downloads/
Docker
containers
available.
docker pull
oracle/graalvm-ce:19.0.2

21. Installation
• tar xfz graalvm-ce.tar.gz
• MacOS X
• mv graalvm-ce-19.0.2 /Library/Java/JavaVirtualMachines/
• Jenv (http://www.jenv.be)
• jenv add <installation director>
• jenv global 1.8.0.212 (can be confusing with Oracle’s OpenJDK)
• Add GRAAL_HOME environment variable (convenience)
export GRAAL_HOME= /Library/Java/JavaVirtualMachines/graalvm-ce-
19.0.2/Contents/home
If graalvm directory own by root complicates installing
additional languages/packages.

22. Maven Toolchain
~/.m2/toolchains.xml

23. Installation Check

24. JDK Differences
Removed Added
javafxpackager gu
javapackager hsdb
jmc js
lli
node
npm
polygot

25. Additional Languages
• Install optional languages:
• gu install R
• gu install python
• gu install ruby
• gu install native-image
• New additions to bin
R Rscript Bundle Bundler Gem
graalpython irb native-image native-image-configure rake
rdoc rebuild-images ri ruby truffleruby

26. Debugging

27. Project Setup - Maven
References
~/.m2/toolchains.xml

28. Maven Coordinates

29. Hello World Example

30. GraalVM API Package
Polygot (org.graalvm.polyglot)
Proxy (org.graalvm.polyglot.proxy)
IO (org.graalvm.polyglot.io)

31. Key Polygot Package Classes
• Context – context for guest language(s), evaluates code
• Engine – execution engine, enables inspection
• Source – source code unit to be evaluated
• Value – polygot value accessed via language agnostic
operations.

32. Interoperability
R
• eval.polyglot('languageId', 'code’)
• eval.polyglot(path = '/path/to/file.extension’)
• export('polyglot-value-name', rObject)
• import('exported-polyglot-value-name’)
Ruby/Python
• Polygot.eval(‘languageId’,’code’)
JavaScript
• Polygot.export/import/eval

33. Interoperability – Data Types
• JavaScript
var BigInteger = Java.type('java.math.BigInteger’);
• R
imageClass <- java.type('java.awt.image.BufferedImage’)
• Ruby
BigDecimal = Java.type('java.math.BigDecimal’)
• Python
import java
BigDecimal = java.type('java.math.BigDecimal')

34. C/C++ Interoperability
clang -g -O1 -c -emit-llvm -
I$GRAALVM_HOME/jre/languages/llvm/include hello.c
Use #include<polygot.h>

35. Nashorn Interoperability
https://github.com/graalvm/graaljs/blob/master/docs/user/
JavaInterop.md

36. Jakarta EE/GraalVM Hello World
• Jakara EE application running on Payara Micro
• Payara Micro, JEE container in a jar file (70 megs)
• Function implemented in each language that:
• Accepts a parameter
• Returns a message
• Use Warm-up bean to service requests fast
• Languages:
• R, JavaScript, Python, Ruby, C

37. Jakarta EE/GraalVM Hello World Demo

38. Express + Jakarta EE
Wrap
• Express web framework for Node.js
• Easy-to-use framework for developing web apps
• Start application in Node, then launch the application container
(Payara Micro)
• Express then calls into Payara Micro to invoke EJBs

39. Express + Jakarta EE
https://expressjs.com

40. Express + Jakarta EE

41. Express + Jakarta EE

42. Jakarta EE + Python
• Use a CDI interceptor to catch runaway scripts
• Seamlessly pass JPA entities to Python to manipulate

43. Future Opportunities!
• Jakarta EE no longer limited to Java?
• Non-Java bindings for other languages
• C++ EJB Singleton?
• Dependency Injection for non-Java objects
• Isolates instead of classloaders
• GraalVM isolates – multiple independent VM instances in JVM
• Improves security
• Limits impact crashes
• Reactive support?
• Many possibilities…

44. Challenges & Limitations
• Window distribution incomplete
• Building & packaging
• Java cannot launch Node.js
• R & Python support is experimental
• Python C API is incomplete
• Practically no packages are supported
• graalpython -m ginstall install numpy

45. Challenges & Limitations…
• Rudimentary Documentation
• On-going changes to GraalVM
• Run headless (NodeJS invoking Java)
• Lots of trial and error…

46. Best Practices
• Warm-up contexts to improve performance
@Startup @Singleton
• Limit access of untrusted scripts
• Monitor and kills runaway scripts

47. GraalVM EE Starter

48. Resources
• Gitter Community
https://gitter.im/graalvm/home
• Medium GraalVM Blog
https://medium.com/graalvm
• Wrapping SQLite
https://habr.com/ru/post/358700/

49. Q&A
Twitter: @ctjava
Email: rcuprak@gmail.com / r5k@3ds.com
Blog: cuprak.info
Linkedin: www.linkedin.com/in/rcuprak
Slides: www.slideshare.net/rcuprak/presentations