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Oscar Guindzberg, Java Developer in Buenos Aires, Argentina
Oscar Guindzberg

Java Developer in Buenos Aires, Argentina

Member since December 31, 2013
Oscar is now available for hire
Oscar Guindzberg, Java Developer in Buenos Aires, Argentina
Oscar Guindzberg

Java Developer in Buenos Aires, Argentina

Member since December 31, 2013
Oscar is a software engineer with 15+ years of experience in the UK and Argentina. He is a Bitcoin & Java expert, co-founder of CreationFlow, and a former university object-oriented design teacher.
Oscar is now available for hire

Portfolio

  • Doosra
    BitcoinJ, Android
  • Strawpay
    BitcoinJ, Android, Payment Channels
  • 37coins
    Bitcoin, BitcoinJ, Blockchain, Multisig, HD Wallets

Experience

  • Java, 13 years
  • JavaScript, 10 years
  • Spring, 3 years
  • Lean Development, 3 years
  • Bitcoin, 2 years
  • Node.js, 1 year
Buenos Aires, Argentina

Availability

Part-time

Preferred Environment

Eclipse, Git, Maven, Heroku

The most amazing...

...thing I've built is CreationFlow, a tool for online collaboration, proofing, review, and approval for digital art production.

Employment

  • Bitcoin Developer

    2015 - PRESENT
    Doosra
    • Made Doosra's hardware wallet work with Andreas Schildbach Android bitcoin wallet.
    Technologies: BitcoinJ, Android
  • Bitcoin Developer

    2015 - 2015
    Strawpay
    • Implemented Strawpay's Stroem protocol on Andreas Schildbach Android bitcoin wallet.
    Technologies: BitcoinJ, Android, Payment Channels
  • Bitcoin Developer

    2014 - 2015
    37coins
    • Developed a REST API based on top of the blockchain.
    Technologies: Bitcoin, BitcoinJ, Blockchain, Multisig, HD Wallets
  • Open Source Developer

    2014 - 2014
    Nimblecoin
    • Created the reference node code for NimbleCoin.
    • Contributed to BitcoinJ.
    • Implemented a missing feature in BitcoinJ to work as a full node.
    • Ran performance tests.
    • Implemented a reference miner.
    Technologies: Bitcoin, BitcoinJ, Java
  • Software Developer

    2011 - 2014
    Freelance
    • Created a recommendation engine that uses the social graph.
    • Created a website and its profitable AdWords campaign in 40 hours.
    • Connected AdWords API and Twilio API.
    • Created a web interface to a complex Excel spreadsheet.
    • Deployed from home to IBM server not accesable from the internet.
    • Hacked the Facebook API to get the friend list of your friends.
    • Beta tested Spring Social and reported bugs.
    • Implemented a Flash visual tool to modify SVG files.
    • Modified and installed a penny auction script.
    Technologies: Java, Spring, Spring Security, Spring MVC, Spring Social, Maven, JPA, Hibernate, Tomcat, PostgreSQL, Jackson, Logback, Tiles, JSP, jQuery, Aspose, Struts, HTML, CSS, Play Framework, Linux, PHP, Selenium, JUnit, Eclipse, Git, Heroku, Amazon S3 & EC2
  • Open Source Node.js Developer

    2013 - 2013
    DemocracyOS
    • Created a user-friendly, open-source, vote-and-debate tool, specially crafted for parliaments, parties, and decision-making institutions that allow citizens to get informed, join the conversation and vote on topics, and adjust how they want their representatives to vote.
    • Transformed the noise that protesters create into a signal that has a clear, direct, and strong impact on the political system.
    • Worked towards the DemocracyOS vision of becoming the operating system serving open and participatory governments.
    Technologies: Node.js, JavaScript, Express.js, npm, PassportJS, MongoDB, Mongoose, Jade, Component, Page.js, Git, Heroku, Amazon S3
  • Co-founder

    2007 - 2011
    CreationFlow
    • CreationFlow is the online collaboration, proofing, review, and approval tool for digital art production. CreationFlow lets you get accurate feedback on work-in-progress design pieces (images, videos, pdf, etc) without the hassle of emails, ftp, and phone feedback. Users can upload files and let others suggest changes using built-in mark-up tool. Raised a $150k seed round.
    • Programmed CreationFlow's MVP.
    • Ran a PR campaign that got us featured on the New York Times: http://goo.gl/cRv5J.
    • Gave webinars that got us clients in 13 different countries.
    • Decided to pivot and throw away 1-year-work code.
    Technologies: Java, Flex, MySQL, Hibernate, Eclipse
  • Software Contractor

    2006 - 2007
    Royal Bank of Canada
    • Implemented statistical analysis software (econometrics/cointegration) over historical/real-time stock prices.
    • Connected to the Reuters API to retrieve real-time stock quotes.
    Technologies: Java, Maven, JUnit, jMock, Selenium, SVN, NanoContainer, Eclipse
  • Senior Java Developer

    2004 - 2006
    Lastminute.com
    • Helped establish offshore development team in Argentina.
    • Redesigned the site layout and content to improve SEO.
    • Implemented a solution for the form resubmition problem in the Hotels section.
    Technologies: Java, Struts, NanoContainer, JBoss, Linux, Ant, JDBC, Velocity, Eclipse
  • Project Manager, Architect, Training Manager, Technical Interviewer

    2004 - 2006
    Globant
    • Recruited 5 of my university students to work for Globant.
    • Created the training area in the company. Organized dozens of tech seminars.
    • Interviewed and evaluated Java developers candidates.
    • Worked on “Mobile Bid system” for Boldt Argentina (http://www.boldt.com.ar). Directed the development of a bid application system for cell phones.
    • Coordinated a group of 2 senior developers.
    Technologies: Java
  • University Professor

    2003 - 2006
    National Technological University
    • Lectured more than 300 students over 3 years.
    • Created course content and exams used by myself and other professors.
    Technologies: Object-oriented Design, Design Patterns, Multithreading, Automated Testing
  • Java Developer

    2001 - 2004
    EDS
    • Implemented the first corporate online banking system in Latin America. EDS is one of the biggest information technology services and solutions company worldwide.
    • The project was the re-engineering of an on-line fund-transfer system from Cobol/CICS to a web-based application. Worked on this project since the beginning. Tasks included front-end and back-end development. For the front-end we used Struts, JSP, and custom tag libraries. In the back-end we used a Services Oriented Architecture, JMX, EJB, and JMS.
    • Was one of the first users of Struts and EJB in Argentina.
    Technologies: Java, Struts, JSP, JMX, EJB, JMS, Tomcat, WebLogic Server
  • R&D Java Developer

    2000 - 2001
    Soluciones Integrales
    • The ERP is designed in 3-tier and fully developed in Java. The front-end is Swing and uses a persistence framework developed by Soluciones Integrales. Task consisted of doing research in Java technologies and to inform the results that could add value to the ERP. Recommended JSDT to program a chat, then Servlets/JSP to give a web-interface to some parts of the application and finally WML to make it compatible for portable devices like PDAs or cell phones.
    Technologies: Java, Swing, Servlets
  • Developer

    1999 - 2000
    Decidir.com
    • Decidir.com is a website that gives commercial risk information (i.e. rejected checks, trials, debts). It also has an online credit card validation system.
    • Initially developed the billing system using Access 7.0. Since it was a small application, was responsible for all the analysis, design, and development. When the company grew, the CTO decided to buy SAP R/3, then was responsible for the data migration from the small bill system to SAP R/3 and end-user training & support. Made first incursion in Java world, developing the online credit card validation system which consisted of a few Servlets and HTML pages.
    Technologies: Access, SAP, Java, Servlets
  • Trainee

    1997 - 1999
    Maer Software
    • Maintained up-to-date the already developed systems.
    • Gave in person and on phone support to end users.
    Technologies: Access, FoxPro

Experience

  • BitcoinJ (Development)
    https://github.com/bitcoinj/bitcoinj

    I am a contributor to the library.

  • Nimblecoin (Development)
  • DemocracyOS (Development)
    https://github.com/DemocracyOS/app

    Online voting platform developed in Node.js: http://democracyos.org/
    Live: http://dos.partidodelared.org/

  • Votamos Todos (Development)

    Experimental online poll system developed in PHP with Facebook API.

  • JuicyCanvas (Development)

    Website for discovering and customizing contemporary art using Java and Flex.

  • Find singles (Development)
    http://findsingles-qa.herokuapp.com

    Experimental site for finding single guys/girls within your Facebook friends and friends' friends. Built in PHP with Facebook API.

  • CreationFlow (Development)

    The startup I co-founded. An online collaboration tool for graphic designers.

  • Blog for Parents (Development)

    Did everything from technology to promotion (minus content). The website helped my partner (a psychologist) to increase her number of patients from 0 to 20 and got her on TV.

Skills

  • Languages

    Java, HTML, JavaScript, PHP, CSS
  • Frameworks

    JavaServer Pages (JSP), Spring MVC, Spring, Spring Security, Selenium, Apache Struts, Adobe Flex, JUnit, Apache Velocity, Express.js, Swing, Hibernate, Java Agent DEvelopment (JADE), Play Framework, Apache Tiles, JPA
  • Tools

    Spring Social, GitHub, Eclipse IDE, Subversion (SVN), Git, Maven, Apache Tomcat, NPM, Servlet, Apache Ant, Mongoose
  • Paradigms

    Model View Presenter (MVP), Object-oriented Programming (OOP), Agile Software Development, Design Patterns, Object-oriented Design (OOD), Unit Testing, Test-driven Development (TDD), Test Automation, Scrum, Extreme Programming, Continuous Integration (CI)
  • Other

    Lean Development, Bitcoin, Ajax, Multithreading
  • Libraries/APIs

    Facebook API, jQuery, Aspose Components, Node.js, JDBC, Jackson, jMock, jQuery UI
  • Platforms

    Heroku, MacOS, Windows, AWS EC2, Linux
  • Storage

    MongoDB, AWS S3, MySQL, PostgreSQL, JSON

Education

  • Bachelor's degree in Software Engineering
    1997 - 2001
    National Technological University - Buenos Aires, Argentina
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