Top Java Developer in Belgrade, Serbia: Dusan Simonovic

Employment

Senior Java Developer
2017 - PRESENT
Gogo, LLC
- Led the development of a back-end tool used by airlines to track usage of the GogoAir in-flight entertainment system in real time.
- Developed microservices (Spring REST services—Spring Cloud, Netflix OSS, AWS).
- Built a deployment process (Netflix OSS, AWS, Spring Cloud).
- Refactored some of the legacy code and migrated data from a data center to the cloud.
- Enhanced security in an existing system.
Technologies: Java, Spring Cloud, AWS
Senior Java Engineer
2018 - 2018
Datasnap inc. (via Toptal)
- Implemented a data processing pipeline for processing trading events from a NASDAQ trading platform.
- Achieved very high throughput and very low latency in processing messages. An amount of 10GB of data (360 millions of trading events) are being processed (including data transformation, aggregation and joins) in less than 20 minutes. End to end latency at the end of project was below 1 millisecond.
- Implemented a pluggable model to support different implementations for input reading and output format.
- Maintained full integration testing in a Docker container.
- Built a full CI/CD pipeline.
Technologies: Java, Apache Kafka, Confluent, Continuous Integration, Continuous Deployment
Senior Java Developer
2017 - 2018
MetaSaas (via Toptal)
- Worked on integrations with various SaaS vendors using mostly REST.
- Reviewed code and handled approvals for other developers.
- Mentored and helped new developers start with integrations.
- Developed an expenses matching mechanism using Expensify API and Elasticsearch.
- Helped create integration testing for new integrations.
Technologies: Java, REST, JWT, OAuth, OAuth 2.0, Elasticsearch, MyBatis
Senior Java Engineer/Scrum Master
2015 - 2017
Endava d.o.o.
- Led the remote element of a technical team.
- Developed core services for the Adobe social media marketing platform.
- Built a link shortening service to be used across the platform.
- Created a label management service for managing content tags/labels.
- Developed an asset service to store user assets to Amazon S3.
- Presented at "Pass it on" sessions to help other members of the company to gain knowledge.
Technologies: Java, Dropwizard, REST, Jersey, JDBI, HBase, MySQL, Git, Scrum, Agile
Web Developer, System Administrator
2010 - 2015
Webcentric d.o.o.
- Contributed to the development of a tool for monitoring competitor prices on online shops.
- Handled the deployment lifecycle of the application.
- Maintained all application environments from development to production.
- Architected a huge MariaDB Galera cluster.
- Mentored juniors and worked on developing them as professionals.
- Set up and maintained a CI environment.
- Developed full-stack features (Java back-end, HTML/CSS/JS on UI).
Technologies: Java, MyBatis, JPPF, MariaDB, Spring Framework, SVN

Experience

Cisco Certified Network Associate (Other amazing things)
Cisco official certification program (CCNA).
Price2Spy (Development)
http://www.price2spy.com
A tool used by web shop owners to monitor their competitors. By using this tool, they get notified about all the changes that happen on their competitor's shops, so they can react accordingly with price or any other adjustments.
Adobe Social - Core Services (Development)
https://www.youtube.com/watch?v=eIoGqPqKAv8
This tool is a huge set of modules that helps enterprise clients set up and maintain their social media marketing campaigns. This project was developed for a world-leading IT company, and its clients are some of the world's top companies.
MetaSaas Platform (Development)
MetaSaas is the best SaaS management tool for medium and large businesses. Manage SaaS vendors, reduce SaaS spend, and manage cloud applications from a single and easy to use dashboard.

As part of the MetaSaas team, my role was to develop more complicated integrations to SaaS vendors and to do code reviews and quality checks for other developers. This involved using REST, OAuth, JWT, and more.
Gogo, Ltd. (Development)
https://www.gogoair.com/
Gogo is a leading in-flight connectivity and entertainment provider. As a member of development team in Belgrade, I was involved in back-end and front-end development of the cloud solution for Airlines to track usage of the system in airplanes. This involved back-end development (Spring cloud, Netflix OSS) and UI (React and Redux).
Datasnap JTrain (Development)
A high-volume/low-latency data processing tool that processes events from the NASDAQ trading platform and produces output. This tool involved data lookup (joins), aggregation, and data transformation.
Get Started With Microservices: A Dropwizard Tutorial (Publication)
https://www.toptal.com/java/dropwizard-tutorial-microservices
Dropwizard allows developers to quickly bootstrap their projects and package applications as easily deployable standalone services. It also happens to be relatively simple to use and implement. In this tutorial, Toptal Freelance Software Engineer Dusan Simonovic will introduce you to Dropwizard and demonstrate how you can use this powerful framework to create RESTful web services with ease.

Skills

Languages
SQL, Java
Frameworks
Spring, OAuth2, Dropwizard, JUnit
Tools
RabbitMQ, Solr
Paradigms
Reactive Programming, Microservices, Back-end Architecture, Continuous Delivery (CD), Scrum, Test-driven Development (TDD), Continuous Integration (CI), REST
Platforms
Amazon Web Services (AWS), Docker, Apache Kafka
Storage
MongoDB, AWS DynamoDB, Microsoft SQL Server, H2, Redis, MySQL, MariaDB, Elasticsearch, HBase, Cassandra
Other
Netflix OSS, Networking
Libraries/APIs
Lucene

Java Developer in Belgrade, Serbia

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Employment

Senior Java Developer

Senior Java Engineer

Senior Java Developer

Senior Java Engineer/Scrum Master

Web Developer, System Administrator

Experience

Skills

Languages

Frameworks

Tools

Paradigms

Platforms

Storage

Other

Libraries/APIs

Education