Category Archives: Conferences

Dev Nexus 2019 – Java Puzzlers NG S04 – JFrog

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Baruch Sadogursky @jbaruch and Viktor Gamov @gamussa

#javapuzzlersng #devnexus

Background

  • Java Puzzlers – 2001 at Oracle Open World. Did many years in a row
  • For later versions of Java
  • Slides with all answers at jfrog.com/shownotes

Survey

  • Only a handful of people on Java 11.
  • Most people on Java 8
  • Unsurprisingly, hardly anyone on non-LTS versions

Note: they requested not posting the answers (even though they are online).

Puzzles

  • If you have an instance variable does This.this.this or this.this compile?

Fun facts that are not the answers

  • Can use non-English characters

How I did/observations

I got 33% (3/9) right. Well, slightly better than guessing randomly :).

  1. I was one of two people to get the first one right! It helps knowing it is a puzzler. I would have guessed compile otherwise!
  2. A lot of people including me got this right. It turns out a new an obscure bit of trivia that showed up in the question but wasn’t relevant to answer it. Fun!
  3. First one I got wrong. That was subtle!
  4. I got this wrong again. I knew the first trick, but not the second. Damn, the compiler is smart!
  5. Three wrong in a row. Again, I saw the first trick, but not the second.
  6. Fourth wrong in a row. Definitely a WTF moment for the answer! (These are great)
  7. Fifth wrong. “Good distribution of answers” – does that mean people voted randomly?
  8. Finally got one right after a while
  9. Ooh a Java 10 one! None of the tricks I could think of in this space are in the question. (Got it wrong of course)

My take

This was fun. They are great showman, have good rapport and had really obscure interesting puzzlers. I also like the showed docs for some of the obscure stuff.

DevNexus 2019 – Containing the Cloud – Wes Widner

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@kai5263499

Containers

  • Represent complexity
  • lots of components
  • notes help manage complexity – write down what doing
  • were not designed to be secure. Were designed for developers to have a feel of a greenfield system
  • just a set of processses
  • developers and ops have different goals. Need different images for debugging vs prod

Tips

  • Log and audit what is in the images. Logging smokes out bad practices. Can’t prevent password, but can catch it at build time
  • Prod image should come from CI/CD pipeline
  • Add forensics info to labels. Ex: git hash. Pretend the cloud is down. Can you explain what is in your image
  • Scan image regularly. The base image will become vunlerable over time. Scan hashes and layers of image
  • Build own scratch image or ami so know what is in it. This is hard, but then you know what is in it
  • Monitor what running to ensure what you intend
  • Config as code
  • Use read only mode in container where possible. Hard to break the container
  • Can tag so only data from specific pods can send certain data. Emerging tech. No standard yet
  • Can taint workers and only certain pods can run

Antipatterns

  • Allowing a broad set of system calls. Makes hard to find atypical patterns. Also broadens attack surface
  • Hypervisor shims – limit what can do
  • Chaos engineering – keeps you honest. A pod running for months and behaves differently on next start is hard to track down.

Cloud maturity

  • Access contol which can push
  • execution logs
  • images from a build system
  • version controk docker configs
  • tagged packets from pods and continuous image scanning

Links: https://www.selikoff.net/2019/03/07/devnexus-2019-containing-the-cloud-wes-widner/

My take

Lots of information. I learned a lot. I also realize how much I’ve forgotten about Kubernettes since i last poked it.

DevNexus 2019 – Mixed Paradigms – Method to the Madness Keynote- Venkat Subramaniam

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@venkat_s

We are problem solvers

Programming languages

  • For communication
  • Expressive and fluent code
  • Uses about 15 languages. Not fluent in any of theM
  • Quadrants – static vs dynamic. Strong and weak typing. Ruby gives a lot of warnings because strongly typed.

“All problems in computer science can be solved by another level of indirection” -David Wheeler

  • procedural – pointers/references
  • object oriented – polymorphism
  • functional – lambdas

Imperative vs declarative

  • more important than OO vs functional.
  • Functional programming is declarative programming with higher order functions
  • imperative is easy to write but harder to read
  • functional is easy to read. Harder to write partly because we spent so many years writing in imperative style
  • Imperative gets harder as problem gets more complex
  • need to focus on both imperative and functional. Hybrid languages
  • lazy execution does not survive mutability. Dont work around compiler errors!

Future – will care more about async than running in parallel. Want to be able to make async without changing structure of code. Kotlin and JavaScript do this now. Java will in a few years with fibers

Changing mind is important. Not whimsickly. But to make progress

Wisdom is realizing there are no absolutes

My take

Great start to the day. I like how so many languages were compared. With humor too. I like how Venkat does a mix of slides and live coding/notes. I really like that he acknowleges that it is ok for things to feel hard