Adam Wasserman, Multithreading Developer in Amsterdam, Netherlands
Adam Wasserman

Multithreading Developer in Amsterdam, Netherlands

Member since May 25, 2017
Adam is particularly interested in multithreaded programming and health care; however, any exciting challenge fits the bill. He believes that a successful project often requires a balance between following and breaking convention. Adam also considers himself personable and an excellent communicator.
Adam is now available for hire




Amsterdam, Netherlands



Preferred Environment

Atom, IntelliJ, Android Studio, Maven, Git, Eclipse, Gradle, Unix

The most amazing...

...thing I've coded is a PGP encryption library for Android, which has been licensed out.


  • Back-end Developer

    2021 - 2022
    International Baccalaureate
    • Designed and implemented a microservice using Spring Cloud that maps data from one format to another. The mapper accepts a tree-like JSON structure and uses a state machine to process it. The input can be quite large in terms of gigabytes.
    • Configured the states in the state machine to operate on one-to-many nodes in the input and on zero-to-many objects in the serialized output. Each output object is translated into HTTP requests and executed by a second microservice, the publisher.
    • Optimized the publisher in terms of mapper and publisher interaction, as well as publisher performance due to the number of requests.
    Technologies: Spring Cloud, Microsoft Azure
  • FHIRcast Developer

    2020 - 2021
    Smart Reporting
    • Created and implemented an FHIRcast client. The client implemented the STU2 FHIRcast specification. The architecture provided pluggable extensions to the functionality (client-specific events and extended event handling). We used the WebSockets flow.
    • Created and implemented an FHIRcast hub. The hub implemented the STU2 FHIRCast specification. The architecture provided pluggable extensions to the functionality (extended event handling). The hub is event agnostic. We used the WebSockets flow.
    • Provided support for a Nuance-specific extension, Powercast, which supported the DiagnosticReport-update event and retained topic state, including versioning.
    • Led the development team and ensured full test coverage. Oversaw the project up to acceptance, then completed handover.
    • Implemented SMART on FHIR-based authorization, when applicable.
    Technologies: Hapi.js, Fast Healthcare Interoperability Resources (FHIR), Docker, Git, Spring Boot, Java, Agile, JPA 2, WebSockets, REST, Asymmetric Encryption, Multithreading, OAuth 2
  • Back-end and Front-end Developer

    2018 - 2020
    Patient Insight
    • Configured and deployed a Vonk FHIR server and a .NET IdentityServer instance to work together for both SMART on FHIR and SMART back-end services (JWT client credentials grant type) authentication.
    • Created a blood pressure dashboard using React for doctors to monitor the condition and treatment of hypertension patients. Observation and patient data were obtained from our FHIR server. The environment was a Google Compute Engine instance.
    • Developed an inbound data feed for the blood pressure dashboard: received continuity of care document (CCD), extracted and transformed data into FHIR resources, and added to the FHIR server. Worked with R4 and DSTU2 data.
    • Created a sample patient population with complete medical histories using Synthea and imported it into our Vonk server for testing purposes.
    Technologies: Google Compute Engine (GCE), C-CDA, Fast Healthcare Interoperability Resources (FHIR), Docker, Angular, React, Node.js, Spring Boot, Java, Git, JPA 2, Healthcare EDI, REST, EHR, Asymmetric Encryption, Multithreading, MongoDB, OAuth 2
  • Front-end Developer

    2018 - 2019
    • Maintained and expanded an existing Android app using Protobuf to interface with the back end.
    • Created several new web-based UIs and web components written in Angular/TypeScript using PrimeNG and NGXS state management. Also refactored and expanded several existing UIs according to new, more modern design.
    • Created unit tests for the UI with the goal of achieving 100% code coverage.
    Technologies: Protobuf, NGXS, Android, PrimeNG, TypeScript, Angular
  • Back-end Developer

    2017 - 2018
    • Created a SAML identity provider for single sign-on.
    • Overhauled the authentication strategies using Passport.js in Express.js.
    • Implemented a message exchange server operating over HTTPS and secure WebSockets.
    • Generated use cases for a complex data feed and produced an initial design that was followed up by the team.
    Technologies: WebSockets, MySQL, Liquibase, SAML, Angular, Node.js, Git, REST, SAML-auth, Single Sign-on (SSO), Multithreading, OAuth 2
  • Back-end and EDI Developer

    2013 - 2016
    Lille Group
    • Developed a HIPAA-compliant electronic health record (EHR) system written in Java.
    • Built a bundle of services that exposed data via traditional web browsers and mobile devices.
    • Created and maintained EDI interfaces based on the HL7 standard for updating patient records with lab results, doctor appointments, and demographics.
    Technologies: RMI, Security, Spring, GWT, Amazon S3 (AWS S3), MyBatis, PostgreSQL, Oracle, Apache Tomcat, Java, Git, Spring Boot, JPA 2, Healthcare EDI, REST, EHR
  • Test Infrastructure Engineer

    2013 - 2014
    SVB | Sociale Verzekeringsbank
    • Established the architecture for running automated test scripts. The system, operated by the government of the Netherlands, makes social welfare payments. Based on IBM mainframes written in COBOL, the tests operated directly on the front end.
    • Designed and implemented a thin-client tool for the management of test scripts in Eclipse.
    • Expanded the core test engine, written in Java and based on the TestFrame framework.
    • Implemented "action words" as defined by the test team.
    Technologies: Security, Spring, Eclipse IDE, Plugin Development, Fusion, Oracle, WebSphere, Apache Tomcat, MyBatis
  • Software Engineer

    2012 - 2013
    Ministry of Justice, Netherlands
    • Optimized a JBoss app based on the ministry's specific application that used FileNet. The application allowed access to documents, some of which were sensitive, based on credentials.
    • Implemented emergency bug fixes on existing applications. A new version of the system was about to be released, but there were reliability problems involving the caching mechanism.
    • Established proper configuration and use of JBoss Cache.
    Technologies: Clustering, Cache, JBoss, JMS, Java, Java EE, JPA 2, Multithreading
  • Software Engineer

    2008 - 2012
    • Developed a risk-management tool for operating, repairing, and expanding huge factories such as oil refineries running 24 hours per day.
    • Created custom modules for client-specific needs. These modules were written in Java and backed by a Drools rules engine.
    • Built an asset management system for factory components, written in Java and backed by Drools.
    Technologies: Oracle, WebSphere, Apache Tomcat, JBoss Drools, JBoss, Spring, Agile
  • Software Engineer

    2011 - 2011
    • Solved a bug emergency in an existing application with a hard deadline for Anva: a company that creates customized software for the insurance industry.
    • Built the software's components which exchanged messages via an ESB. The problems involved remote access via RMI of the ESB registry.
    • Reviewed the message exchange mechanism and made recommendations on improvements.
    Technologies: RMI, JBoss, Java, Multithreading
  • Software Engineer

    2011 - 2011
    I Get It!
    • Developed a prototype for a menu application intended for restaurant chains which included a proprietary content management system.
    • Worked with Native Android (UI and services).
    Technologies: Android
  • Software Engineer

    2010 - 2010
    • Worked for CliqDigital which maintained a proprietary premium text messaging platform written in Perl. It was based in part on something that I had written for its predecessor, Blinck. My intimate knowledge of its inner workings was a unique qualification for this project.
    • Replaced the existing system with one written in Java using J2EE technologies. There was no documentation, but the existing system was the baseline and the new system had to behave exactly the same.
    • Created, with two junior programmers, a suite of E2E tests that functioned as the definitive technical determination of success.
    Technologies: MySQL, Perl, JBoss, JMS, EJB 3, Apache
  • Software Engineer

    2009 - 2010
    • Adapted an existing premium text-messaging platform for a client's specific needs. Users subscribed via rich front-ends written in Flash and the traffic was provided by advertising affiliates.
    • Implemented the routing, tracking, and reporting services for advertising affiliates.
    • Worked with third parties to create interfaces for data exchange: status reports, subscriber activity, and payment.
    Technologies: Multithreading, RESTful Development, REST APIs, MySQL, PHP, Perl, Apache
  • Software Engineer

    2007 - 2008
    Compare Group
    • Worked for the company Compare Group which operates several sites in the Netherlands and Belgium where consumers can compare online prices for various projects. The platform scraped target websites and aggregated the data encountered there (products and attributes). Written in Java and backed by a series of SOAP web services.
    • Conduced emergency bug-fixing; the platform was delivered by a third party full of errors and missing major functionality. It had a hard deadline to get it working. Worked closely with a test team in rapid iterations until all tests passed.
    • Introduced AOP as a non-intrusive technology to diagnose, supplement, and correct functionality.
    Technologies: Spring MVC, Spring, SOAP, Apache Tomcat, AOP, JAXB, Hibernate, Java
  • Software Engineer

    2007 - 2007
    • Worked in a team on a variety of small projects, as needed. Venspro operated the Greetz brand of online cards and flowers.
    • Implemented the real-time data transformation as well as credit-card, bank transfer, and mobile billing interfaces.
    • Developed a thin HTML client with a Java/Spring back-end.
    Technologies: Spring MVC, Spring, Oracle, Apache Tomcat, Hibernate, Java, Java EE, Multithreading
  • Software Engineer

    2006 - 2007
    • Swapped-out JBossMQ for the more advanced JBossMessaging in their proprietary premium text-messaging platform. Dealt with a resolution of race conditions exposed by the update.
    • Built a freestanding interface to manage (start, stop, reload) endpoints using JMS and EJB. An endpoint is a combination of gateway and mobile shortcode where text messages originate and can be received.
    • Created a strategy for running the system in a cluster of JBoss nodes.
    • Implemented the strategy and demonstrated its viability in a test environment.
    • Deployed code changes to production in a non-clustered environment.
    Technologies: Clustering, Remoting, Messaging, JBoss, SOAP, JMX, JMS, Enterprise Java Beans (EJB), Java, Java EE, Apache
  • Software Engineer

    2005 - 2006
    Philips IP&S
    • Developed an online product license verification system where customs agents checking cargo at the border could use the system to request documents confirming that the products were genuine.
    • Created a series of SOAP web services for receiving requests. The product universe varied considerably, a fact which had an impact on the schema describing our XML.
    • Ensured that the requests could be processed asynchronously. The software was backed by a state machine written in Java. The eventual output was a PDF sent via email.
    Technologies: SAP, Enterprise Java Beans (EJB), SOAP, Java, Java EE, Multithreading
  • Architect | Software Engineer

    2003 - 2005
    Blinck International
    • Designed and implemented a platform written in Perl for delivering premium content via SMS/text-messaging to mobile users all over the world.
    • Conduced Apache configuration and optimization including Mod_perl.
    • Created and implemented modules to interface with gateways (text-messaging providers) for the purposes of sending text-messages, receiving status alerts, and billing.
    Technologies: Perl, Apache
  • Software Engineer

    2003 - 2003
    • Worked on a single sign-on application based on the SAML and Liberty specifications for identity management.
    • Created a web-based application to keep track of billable hours (for internal use only).
    • Experimented with EJB technology deployed into WebSphere.
    Technologies: ATG, SAML, SOAP, Apache Struts, Enterprise Java Beans (EJB), WebSphere, Apache Tomcat, JBoss, Java, SAML-auth, Single Sign-on (SSO)
  • Software Engineer

    2002 - 2003
    Expresso Paper Platform
    • Worked in a team to build and expand an eCommerce message exchange connecting clients with suppliers in the paper industry. Orders arrived via SMTP (email) and were processed in a queue-like system (ECXpert), each segment in the pipeline feeding into the next. Message exchange between stops in the pipeline occurred via SOAP. ECXpert was cumbersome, CPU-intensive, and no longer being actively supported.
    • Replaced the ECXpert proprietary system with a series of JMS components replicating stages in the pipeline and a daemon using JavaMail to retrieve incoming SMTP messages and submit them to the first stage.
    Technologies: Oracle, XML, JavaMail, LDAP, JMS, Java
  • Software Developer

    2002 - 2002
    Holland House
    • Benchmarked an existing, proprietary printer spooling system and set a baseline for further improvement.
    • Designed a new interprocess communication layer for their printer management system based on JMS.
    • Worked directly with the architect to create prototypes as proofs-of-concept in migrating architecture from a proprietary system to a J2EE-based system.
    Technologies: Solaris, XML, JMS, JBoss, Java, Multithreading
  • Software Engineer

    2001 - 2001
    • Designed and implemented a distributed content-management system for streaming video and audio. The content was used in a variety of branded media portals. Meta-data about the content was stored in LDAP. The web pages themselves were generated via JSPs with access to LDAP.
    • Worked directly with Flash designers to create a tool to allow them to plan content in time slots, similar to TV programming.
    • Ensured that the content management tool had to populate LDAP and copy the corresponding media files from the designer's machine to the appropriate locations on the server.
    Technologies: JBoss, LDAP, JSP, Enterprise Java Beans (EJB), Java
  • Software Developer

    2000 - 2001
    • Worked on an online bill presentation and payment system.
    • Created a payment interface for Equens (Interpay).
    • Functioned as the team lead.
    Technologies: Java
  • Software Developer

    1999 - 2000
    • Worked on a web traffic tracking system written in Perl and Java with both free and paid services.
    • Created a JNI component written in C for performing UNIX-specific functions required by the platform.
    • Developed an interface in Java between a remote JDEdwards system and NedStat's internal system.
    Technologies: JD Edwards, PHP, Perl, C, JNI, Java
  • Software Developer

    1997 - 1998
    Community of Science
    • Worked on a system for providing access to paid academic articles online. Clients could subscribe with various levels of access.
    • Kept track of user sessions which had to be done manually.
    Technologies: Perl
  • Software Developer

    1996 - 1997
    Credit Management Solutions
    • Created one of the first online tools accepting applications for consumer car loans.
    • Developed a Windows DLL for processing loan results and making them available to the online system.
    • Worked with the team in charge of the core credit scoring engine to ensure the online system's compliance with various state laws.
    Technologies: C
  • Software Developer

    1996 - 1996
    Applied Physics Lab
    • Helped to develop software that was intended to predict mechanical problems in tank engines before they actually occurred. It involved real-time data acquisition and comparison to previously obtained data profiles.
    • Worked closely with a mechanical engineer to make the physical data in the form of electric signals accessible to a computer system programmatically.
    Technologies: C


  • Software Entropy Explained: Causes, Effects, and Remedies (Publication)
    In this article, Toptal Freelance Developer Adam Wasserman explains what software entropy is, what causes it and how it manifests itself, and what can be done to prevent it or mitigate its effects.


  • Languages

    Java, SAML, JavaScript, C, Perl
  • Frameworks

    Spring Boot, Angular, OAuth 2, Apache Struts, JSP, JNI, Hapi.js
  • Tools

    SMART on FHIR, Git, Apache Tomcat, Apache, Eclipse IDE, Google Compute Engine (GCE), JBoss Drools
  • Paradigms

    HL7 FHIR Standard, REST, Agile, Fast Healthcare Interoperability Resources (FHIR), AOP
  • Other

    Multithreading, Public-key Cryptography, SAML-auth, SMS, Asymmetric Encryption, EHR, SOAP, Healthcare EDI, Single Sign-on (SSO), EJB 3, LDAP, RMI, Plugin Development, Remoting, NGXS, WebSockets, C-CDA, Enterprise Java Beans (EJB), Spring Cloud, Microsoft Azure
  • Libraries/APIs

    PrimeNG, Node.js, JMS, MyBatis, Java RMI, JPA 2, React, JAXB, JMX, JavaMail, Liquibase, Protobuf
  • Platforms

    Android, Jakarta EE, Java EE, JBoss, WebSphere, Oracle, Linux, Docker, Eclipse, Unix
  • Storage

    MySQL, PostgreSQL, Cache, Amazon S3 (AWS S3), MongoDB


  • Bachelor of Science Degree in Computer Science
    1991 - 1995
    Johns Hopkins University - Baltimore, MD, USA

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