Danijel Gornjaković, Developer in Belgrade, Serbia
Danijel is available for hire
Hire Danijel

Danijel Gornjaković

Verified Expert  in Engineering

Full-stack Java Developer Developer

Belgrade, Serbia
Toptal Member Since
June 29, 2020

Danijel is an accomplished full-stack Java developer with more than a decade of professional experience. He is well-versed in both back-end and front-end work, databases (SQL and NoSQL), and DevOps. Danijel puts clients' needs first and makes sure they get optimal value from software.


Cassandra, Neo4j, MongoDB, Angular, Spring Data, Spring, Java
Adama Regstore
YUI, Alfresco, Java
Adama Public Website
JSON, FreeMarker, jQuery, Liferay, Java




Preferred Environment

Java, Eclipse, IntelliJ IDEA, Linux, Windows

The most amazing...

...software I've worked on was a big data project combining three NoSQL databases—MongoDB, Neo4j, and Apache Cassandra—to deliver fast read and write throughput.

Work Experience

Lead Developer

2018 - 2020
  • Developed a validation module built with MongoDB and Kafka messaging with Angular to visualize the data.
  • Designed and developed a forecast data module with the Apache Cassandra database.
  • Configured and maintained Jenkins and GitLab CI/CD pipelines for various docker and GitFlow jobs.
  • Developed a master data model and import logic using Spring Data and Neo4j.
Technologies: Cassandra, Neo4j, MongoDB, Angular, Spring Data, Spring, Java

Lead Architect

2017 - 2018
Adama Regstore
  • Led a team of four developers as both the scrum master and lead architect. I solicited requirements from the client and made sure the team delivered them as intended.
  • Established the architecture of the project; handled DevOps tasks to configure CI/CD using Bamboo; and set up the development, QA, and production environments.
  • Implemented and oversaw the release process, which required an initial import of more than 100,000 documents with the client's metadata.
  • Developed an OCR module using Adobe Backend Services API and Apache Solr search implementation.
Technologies: YUI, Alfresco, Java

Senior Full-stack Developer

2016 - 2017
Adama Public Website
  • Developed the migration module that would transfer all content from an SQL database to a JSON format compatible with Liferay and then oversaw the import.
  • Participated in the initial setup and configuration of the Liferay environment.
  • Developed several portlets in Liferay with Spring MVC and jQuery.
Technologies: JSON, FreeMarker, jQuery, Liferay, Java

Senior Full-stack Developer

2015 - 2016
Adama Knowledge Hub
  • Co-developed the data model for a Neo4j database to represent a real-world use case for agricultural farmers in relation to crops and pesticides.
  • Handled back-end tasks to integrate Neo4j and Spring MVC into Liferay Portal.
  • Wrote and optimized Spring Data queries to meet the non-functional requirements of thousands of users needing runtime search results.
Technologies: Liferay, Neo4j, Spring, Java

Full-stack Developer, Scrum Master

2014 - 2015
  • Co-developed a portlet that communicates with an IoT device to control smart home ACs. The device used XMPP protocol for communication.
  • Developed the UI of the portlet that would mimic the UI of the remote device to control the AC. We built the SVG UI using Raphael.js library.
  • Acted as the scrum master, ensuring that teams adhered to the Scrum framework.
Technologies: Raphaël, XMPP, Liferay, Java

Full-stack Developer

2013 - 2014
  • Built and maintained a module integrating IBM Notes mail client into Liferay. The data was fetched using CORBA remote procedures.
  • Developed the logic to write emails using RichText editor and forward those emails from Liferay to a Lotus Notes server.
  • Analyzed the API possibilities of the IBM Domino database and designed the concept for how that data could be mapped to the common model we used.
Technologies: IBM Domino, Java EE, Liferay

Full-stack Developer

2010 - 2013
Heliant (Health Information System)
  • Developed a standalone business intelligence module for managing the inventory of medicines and other medical equipment.
  • Implemented ad hoc reporting using prepared queries and a custom-built UI.
  • Participated in release management and deployment of a new version to more than 50 servers.
Technologies: CSS, HTML, Jakarta Server Pages (JSP), JavaScript, MySQL, Hibernate, Java

Big Data Project with MongoDB, Neo4j, and Cassandra

I participated in a big data project with terabytes of data being imported and exported on a daily base. The project required a fast read and write throughput, so we had to model the data to different NoSQL databases and decouple and parallelize the import and export process. Communication between microservices was done using Feign clients and Kafka. The GUI for managing the workflows and querying the data was built using Angular and Angular Material.

Adama Public Website

I co-developed a public Liferay and Java-based portal. Each country had its own site (50 in total) with shared content types and a common look and feel. I built the migration module taking the data from the older SQL database and mapping it to a JSON module compatible with Liferay. I also built various portlets based on design and functionality requirements. And, finally, I worked on the LDAP and ADFS integration to build a single sign-on experience for the web editors.
2010 - 2011

Master's Degree in Computer Science

University of Belgrade School of Electrical Engineering - Belgrade, Serbia

2006 - 2010

Bachelor's Degree in Computer Science

University of Belgrade School of Electrical Engineering - Belgrade, Serbia


Certified Liferay Portal Developer

Liferay, Inc


Professional Scrum Master, Level 1 (PSM-1)



Neo4j Certified Professional



Certified Professional for Requirements Engineering

International Requirements Engineering Board (IREB)


Java Certified Developer



YUI, jQuery, Raphaël


Jira, Jenkins, Bamboo, IntelliJ IDEA, Alfresco, FreeMarker


Neo4j, Spring Data, NoSQL, MongoDB, MySQL, Cassandra, JSON


Spring, Angular, Hibernate, Jakarta Server Pages (JSP)


Java, SQL, JavaScript, HTML, CSS


Windows, Linux, Eclipse, Java EE, IBM Domino




Apache Cassandra, PSM-1, Liferay, XMPP

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring