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After a first successful European excursion in 2012, JRubyConf is back. Bigger and better — this year as a two-day, single track conference.

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Meet our speakers

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    Image of Charles Nutter

    Charles Nutter

    Red hat Inc.


    Charles works on JVM languages at Red Hat, focusing on Ruby but expanding to other languages soon. He has worked on JRuby for the past eight years and has been a JVM enthusiast since Java 1.0. Charles hopes to make JRuby the best Ruby implementation for high performance, big data, and heavy loads, and to use lessons learned from JRuby to help the JVM and other languages that run on it meet their potential.

    “Optimizing Ruby”

    Over the past 6 years, my focus on the JRuby project has usually been performance. I've worked on JRuby's bytecode compiler, optimizations to the runtime and core classes, improvements to memory use and allocation rates, and the removal of concurrency bottlenecks. Over that same time we've managed to increase JRuby's performance by orders of magnitude, in some cases approaching the speed of compiled Java.

    This talk will go over the major performance leaps we've had during that time, starting with the disabling of ObjectSpace and proceeding through recent enhancements like instance-variable packing and backref framing. You will gain a better understanding of what makes Ruby fast or slow, how you can write more efficient Ruby code, and what implementations like JRuby are doing to make Ruby perform even better in the future.

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    Image of Tom Enebo

    Tom Enebo

    Red hat Inc.


    Thomas Enebo is the co-lead of the JRuby project and an employee of Red Hat. He has been a practitioner of Java since the heady days of the HotJava browser, and he has been happily using Ruby since 2001. Thomas has spoken at numerous Java and Ruby conferences, co-authored "Using JRuby", and was awarded the "Rock Star" award at JavaOne. When Thomas is not working he enjoys biking, anime, and drinking a decent IPA.

    “JRuby Pain Points”

    All applications and libraries have their pain points. JRuby is no exception. Thomas will examine JRuby's pain points and reflect on the perception of pain. He will finish by talking about some future plans to address these pain points.

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    Image of Theo Hultberg

    Theo Hultberg



    Theo is Chief Architect at Burt, a Göteborg based big data startup that wants to revolutionize the advertising industry by showing that there's more to ad analytics than clicks. He learned to build distributed systems the hard way by building a real time analytics platform that now handles billions of requests per day.

    He is a frequent speaker at developer conferences around Europe, where he favors topics such as JRuby, big data and distributed systems. In his hometown of Göteborg he co-organizes the Ruby, Scala, JavaScript and distributed systems user groups.

    But his only real claim to fame is that he has more reputation on Stack Overflow than both Jeff and Joel.

    “Chasing the Elephant”

    An account of my big data adventures with JRuby. War stories from battling with storms, scaling mountains and speaking with oracles.

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    Image of Benoit Daloze

    Benoit Daloze



    Benoit is an open-source evangelist and a benchmark freak. He is now an MRI committer and enjoys contributing to many projects including JRuby, Rubinius and Homebrew. He has been working last summer with the Google Summer of Code program and had the chance to have @enebo as a mentor.

    He started talks about benchmarking at the Belgian Ruby User Group a couple years ago and gave a talk at JRubyConfEU/eurucamp last summer. Between these, he gave various talks about Ruby and Git at my university ACM Student Chapter. attended a bunch of conferences including RubyConf, EuRuKo, ArrrrCamp and of course eurucamp.

    “Performance in JRuby: How fares the JVM in day-to-day tasks?”

    About everyone has heard JRuby is fast, but how fast is that?

    This talk is about giving you a concrete idea of it, with realistic use-cases of popular libraries, efficient programming contests solutions and day-to-day tasks from reading a file to analyzing a web app. There will be a comparison with other Ruby implementations as well as with various languages and VMs, highlighting pros and cons of the JVM.

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    Image of Jano González

    Jano González



    Jano is a developer, amateur musician and addicted to conferences. He has created from small webapps to complex enterprisey architectures and has spoken in plenty of latin american conferences, currently the CTO of HopIn. During his free time he plays music and tries to practice sports (without much success).

    “Ruby for Java minds”

    Maybe after years of Java you have adopted an style that's not immediately transferable to Ruby. In this talk you will know the experience of someone who spent many years programming in Java before falling in love with Ruby. We will explore how to stop worrying and embrace dynamic typing, adopting a more declarative style of programming and some of the nice things you can do now that you are using Ruby.

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    Image of Javier Ramirez

    Javier Ramirez



    Javier is a web developer working mainly in Ruby on Rails projects since 2006 and one of the founders of teowaki, a web service designed to make software development teams happier.

    He is also the author of the book “Aptana RadRails: An IDE for Rails Development” and an active member of the Ruby scene, being a founding member of the Spanish Rails Conference, the Spanish Ruby Users Group (SRUG), madrid-rb, the Ruby users group in Madrid, and the Spanish Railscamp.

    He is currently based in London —with regular trips to Madrid. In the past he’s worked in Zaragoza, Brescia, New York, Barcelona and Madrid.

    “Usable REST APIs”

    With the adoption of REST, the proliferation of smartphones and tablets, and the second coming of JavaScript, exposing our applications as a service is now more important than ever.

    Rails or Sinatra make really easy to create a (kinda) RESTful API but, in many occassions, these APIs are designed without really thinking on the developers that will have to use them.

    I want to talk about some of the points that can help making your API more developer-friendly. Some of the areas I’ll cover will be discoverability, authentication, headers, formats, parameters, documentation and tools.

    I will also provide a few tips about how to build your application first as a service, then adding the web/mobile/presentation layer.

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    Image of Silvia Schreier

    Silvia Schreier



    Silvia is a consultant at innoQ with a strong scientific background in developing RESTful applications. She has just started to explore the world of Ruby (on Rails) and co-organized Rails Girls Rheinland.

    She enjoys diving into new technologies with a focus on developing RESTful applications, e.g., with NodeJs and Clojure, and using NoSQL databases.

    Up to now she gave talks on scientific conferences but now it is time to solve real problems and share the experiences.

    “RoR + DynamoDB = ?”

    We are currently developing a Ruby on Rails application with Amazon's DynamoDB. Using a NoSQL cloud service and especially DynamoDB with its particular restrictions entails a lot of challenges.

    We will share our experiences using DynamoDB in general and in combination with Ruby (and Rails) to help you to decide if you want to use DynamoDB for your project (or not). We also provide a list of things you should to keep in mind if you start using DynamoDB. These range from managing your database, over mapping your model to the database, up to testing. Furthermore, we present the design and technical details of our persistence module.

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    Image of Tim Lossen

    Tim Lossen



    "Amongst our weaponry are such diverse elements as: fear, surprise, ruthless efficiency ..... and an almost fanatical devotion to the Pope."

    Backend Engineer at Wooga.

    “All Your Cores Are Belong To Us”

    It is 16:39 on a friday afternoon when your boss walks over. "I urgently need an overview of the number of Archer Towers that players have built. Could you please generate a little histogram before you go home?" You start to sweat. There are over a million player files on disk ...

    Kernel threads -- or being able to utilize all cores from a single process -- is a JRuby killer feature. In this talk, I will show how a fully operational "Mini Hadoop" can be built in fifty lines of JRuby. I will also demonstrate live on stage that it saves the day in the imaginary scenario described above.

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    Image of Tobias Pfeiffer

    Tobias Pfeiffer



    Tobi is a clean coder, Rubyist, learner, teacher and agile craftsman by passion. He organizes the Ruby User Group Berlin and contributes to shoes and hacketyhack. He has a special neck for teaching, which is why he is a frequent coach at Rails Girls Berlin and also started to teach a course at a university recently. Right now he is a happy Google Summer of Code student working on shoes4.

    To get an idea of what he is interested in and what he does you may check out his blog.

    “Shoes - The Ruby way to GUI applications”

    We build web applications and command line applications with Ruby - but what about graphical desktop application? There used to be this Shoes thing, but isn't that dead?

    No it's not! Shoes4 is being developed right now by a dedicated team. Let me tell you all about it and introduce you to this beautiful DSL I fell in love with.

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    Image of Ben Lovell

    Ben Lovell



    Ben is a regular contributor to open-source, agile proponent and harbours an almost unhealthy obsession for all things concurrent and distributed. Ruby, Go and Scala are his first loves. Beards a close second.

    He currently works for digital agency 1minus1.

    “Live long and prosper with Celluloid and JRuby”

    In this talk you'll learn about the Celluloid ecosystem. We'll take a glance at:

    • Celluloid - the OOP & Actor model based concurrency framework
    • Celluloid::IO - an evented I/O framework
    • DCell - distributed Actors for Celluloid
    • Reel - the Celluloid::IO powered web server

    I'll cover the Actor model - Celluloid's inspiration for their approach to concurrent objects. How we can best achieve concurrency without mind-bending synchronisation, mutexes, deadlocks and all in idiomatic and simple to grasp Ruby.

    We'll finish up by briefly covering JRuby and why it's my preferred Ruby VM for concurrency with Celluloid.

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    Image of Martin Boßlet

    Martin Boßlet



    Martin is a freelancer by day, by night he is also a member of ruby-core, one of the maintainers of the Ruby OpenSSL extension and the author of krypt. Cryptography is his passion and he truly enjoys it, even if it means being the nerd among nerds for the rest of his life. He's been helping the European Commission to implement a digital signature platform over the past years, and this was also the reason for krypt - so that he could do it in a sane language for once. He recently discovered blogging as a compensation for not haunting other people with lengthy emails anymore.

    “krypt & jruby - cryptography's new best friends?”

    As of JRuby 1.7.3, krypt is being shipped with JRuby by default. Currently, krypt is being used to provide missing functionality of the OpenSSL extension. Chances are you may be using krypt today without even realizing it.

    But krypt's goals go beyond just being a fill-in for OpenSSL - the ultimate goal is to replace the OpenSSL extension entirely. See for yourself how the Java parts of krypt enable us to run the exact same code on all Rubies - no more second class citizens, no strings attached. You're fed up with overcomplicated APIs for everyday things like securing your passwords or encrypting your data? krypt provides cryptography for actual human beings with simple and clear interfaces. There's a dead-simple API if all you care about is security, but there's also full control for the guys in the ivory towers. Find out how to extend krypt's functionality by integrating Java cryptography libraries.

    Finally, be a witness of something that no other JRuby (or Java) cryptography library can give you today: access to arbitrary C crypography libraries without having to change your actual Ruby code.

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    Image of Lukas Rieder

    Lukas Rieder



    Lukas evolved from a webdesign background to a backend developer. A couple of years ago I was fiddling with HTML, CSS. Now I am building all sorts of stuff that runs on servers. I have a great passion for simplicity, empiricism and of course Ruby! I am currently working for Wooga, a social games company in Berlin. But my biggest passion in life is my family, a lovely wife and two daughters.

    You can meet me occasionally at the Ruby User Group Berlin.

    “Stateful Application Server”

    After more than one year of development, Wooga is heading for the global launch of its game "Kingsbridge"!

    This is the first game at Wooga with a backend written in JRuby!

    The talk includes an introduction to the problems that were solved by choosing a stateful applicaton server.

    I will explain constraints, benefits and obvious differences to traditional database backed application servers.

    • Safely sharing state in a concurrent environment using JRuby
    • Using Java concurrency utils in JRuby
    • Sample problems solved, backed up with code
    • Practical tips for capacity planning

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    Image of Marek Jelen

    Marek Jelen

    Red Hat Inc.


    JRuby enthusiast, Open-Source contributor, PaaS advocate, Red Hat employee

    “JRuby on PaaS using Torquebox”

    Even though JRuby is not officially supported on OpenShift, it's very simple to get it there working. In my talk I would like to talk about why I think OpenShift is a great platform and JRuby on it makes sense. However this would be too simple. In the second part we will get rid of all the stacks and will deploy Thick (my hobby project - Netty based web server) on OpenShift but straight on top of Red Hat Enterprise Linux.

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    Image of Joe Kutner

    Joe Kutner



    Joe is a freelance Ruby developer in the United States. He's built Ruby and JRuby applications for small startups, large enterprises, and every size company in-between. He's also authored two books from the Pragmatic Bookshelf: "Deploying With JRuby" and "The Healthy Programmer." Joe contributes to a number of open source projects including TorqueBox and Warbler.

    “TorqueBox: This Ain't Your Grandpa's Enterprise”

    If the Java ecosystem is keeping you from deploying your Ruby applications on the JVM, then wait no more. You can deploy your JRuby web apps to the cloud using new products from Heroku, RedHat, EngineYard, Google, Amazon, and others. You'll learn how one git push gives you access to true multithreading, clustering, messaging, advanced garbage collection, just-in-time compilation and much more. After this talk, you'll be able to deploy TorqueBox, Trinidad, and Warbler to a variety of cloud platforms.

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    Image of Josh Kalderimis

    Josh Kalderimis

    Travis CI


    Josh is a lover of coffee, bacon, long walks on the beach, and continuous integration. As a Travis CI founder he spends his day getting his hands dirty with code, customer support, virtual machines, APIs, and devops. And if you look closely enough you can find his mantra 'shipping technical debt daily' tattooed on his body!

    “JRuby Running All The Things”

    JRuby has been at the heart of Travis CI for over two years now. Our SOA based architecture has allowed us to use the best Ruby for the job, and in most cases this has been JRuby. From our log processing, to our build infrastructure, to our background jobs, JRuby is everywhere.

    No matter what technology you use at the heart of your business you are bound to have the 'HUZZAH' moments, and the 'WAT THE FUUU' moments, and we have had our fair share of these.

    This talk covers not only our code and what we did right and wrong, but also a bit of the Ruby eco system, and how we can all improve it.

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    Image of Martin Mauch

    Martin Mauch



    Martin is innovation manager at crealytics, a company dedicated to shaking up the PPC advertising market with Profit-Driven Search Marketing and their software camato.

    Martin loves to connect and combine ideas and dream about the future of software development.

    Ruby, Scala and Bavarian are his favourite languages and he fluently switches between the three.

    “JRuby and Scala - not even a compiler can separate us!”

    Ruby and Scala are both beautiful languages that allow for functional, object-oriented and meta-programming. Both have their uses and strengths, so why not become a shape-shifter, a traveller between worlds? Using simple meta-programming facilities one can join JRuby and Scala to get the best out of both. We will take a simple RSpec'ed JRuby program and port it to Scala along green tests.

    You'll get an idea of the many similarities between Ruby and Scala, where the two differ and what a compiler can do for you.

    You will see how Scala can be taught to talk to dynamically typed languages without the compiler breaking into tears and you will see how JRuby can use Scala as a nitro-booster for performance-critical parts.

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    Image of Tom Stuart

    Tom Stuart



    Tom works in Berlin as a backend developer for Soundcloud and spends a decent chunk of his spare time teaching beginners to program with Ruby. He is a known curmudgeon and often wishes he were a philosophy teacher.

    “The linguistic philosophy of Ludwig Wittgenstein”

    What is truth? What is the meaning of a word? Are these even good questions? What does this have to do with programming? Learn, or possibly not, the answers to some of these questions in an overview of the philosophical work of Ludwig Wittgenstein.

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The Venue

Berlin impression

Berlin, Berlin! Europe’s creative hub provides the perfect setting for
The conference will be held at the beautiful Heimathafen Neukölln (Karl-Marx-Straße 141, 12043 Berlin).

Heimathafen Neukölln, Logo

Heimathafen Neukölln, Stage
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