Ola Mattsson
Senior Java Developer
Stockholm
Summary
With a strong background in system development, particularly in the Java ecosystem, and experience in both new development and management of mission-critical systems. I bring a combination of technical expertise and a robust agile working methodology to your team. Throughout my career, I have successfully worked with systems supporting thousands of concurrent users, optimizing transaction-intensive applications for high performance and reliability. Additionally, I have actively participated in architectural decisions and effectively bridged the gap between IT and operations to ensure sustainable solutions. Thriving in a technical leadership role, I leverage my deep knowledge of Java, microservices, databases, and cloud solutions to coach and empower the team. Agile work comes naturally to me, as demonstrated in my recent assignments at Handelsbanken and Worldline where I worked within the SAFe framework to support long-term planning and synchronize development efforts across teams. Notably, I excel at solving problems under pressure, such as enabling more users to access resource-intensive systems simultaneously without negatively impacting business operations. My passion for staying up-to-date with the latest technologies and trends in software development enables me to quickly adapt to new technologies and contribute to the team's skill development.
Overview
25
25
years of professional experience
4
4
years of post-secondary education
2
2
Languages
Work History
Senior System Developer
Handelsbanken IT
02.2023 - 12.2024
- I have been responsible for maintaining Handelsbanken's web service for private customers when it comes to debit and credit cards
- I have also been a leader in building a new system to connect Handelsbanken's card products to Apple Pay, Samsung Pay and Mastercard's Click to Pay service
- I'm well acquainted with tools like IntelliJ, Git, TeamCity, SonarQube, and Artifactory
- In addition, I have experience with several frameworks and tools, including Bitbucket, JSON and JMS
- My goal is to continue to develop their skills and contribute to successful software development projects
- Technical environment: Java, IntelliJ, SonarQube, Artifactory, Kibana, JSON, SQL, REST, LIKE, Team City, Bitbucket, Mockito, Git, Agile, SAFe, TDD, BDD, Junit
Senior System Developer
Worldline (formerly Bambora)
04.2021 - 02.2023
- Company Overview: Worldline has a business concept to help companies grow with easier opportunities for payments
- I worked as a Lead Developer within a development team and had a key role in the design, development and technical decisions for two complex systems
- In the work with the customer database I developed, my focus was to build a new kind of generic, configurable database with a type system that made it possible to define relationships between data points
- To ensure history management and immutability, I implemented a timeline-based storage model where all changes were preserved
- I was responsible for the encryption strategy that made the database GDPR compliant by making data unreadable when legal requirements allowed it
- I also drove the development of an event-driven integration between a risk assessment system and the customer database
- In both systems, I used Spring WebFlux / Project Reactor (Flux/Mono) to handle asynchronous data streams, which improved performance and scalability
- My role involved solving challenges in real-time data management and distributed systems, as well as guiding the team in best practices for Reactive Programming
- The IT organization consisted of 100+ people, and I collaborated with both developers and the business side to ensure a stable and future-proof architecture
- Worldline has a business concept to help companies grow with easier opportunities for payments
- Technical environment: Java 17, Spring Boot 2 & 3, Microservices, REST API, Infrastructure as Code, Reactive Programming, CI/CD Jenkins, AWS ECS, AWS Lambda, AWS Aurora, PostgreSQL, AWS SQS, Python, Event-driven, Docker, JSON, Test Automation/JUnit, Git, Agile / SAFe, TDD, Junit
Senior System Developer
Bolagsverket
08.2020 - 04.2021
- Company Overview: The Swedish Companies Registration Office must create the conditions for a business community where you can trust each other
- I worked in an agile development team that was responsible for creating a REST API platform, which third-party actors can create a user interface against
- My role was to write Spring Boot microservices for the platform with BDD
- The Swedish Companies Registration Office must create the conditions for a business community where you can trust each other
- Technical environment: Java, Spring Boot 2, Microservices, REST API, CI/CD, Junit, JSON, Test Automation, Git, BDD
Senior System Developer
Knowit AB
08.2019 - 06.2020
- Company Overview: Knowit is one of the largest IT consulting groups in Northern Europe
- I was responsible for the development of a self-developed event booking solution
- The tasks were to develop architecture, design and solution proposals in collaboration with decision-makers and stakeholders
- Lead the development of a microservices-based solution using Spring Boot (Java 13) in Docker containers on AWS
- Implement communication between microservices through Apache Kafka and configured Kafka servers in AWS
- Be responsible for the CI/CD pipeline in CircleCI, including code retrieval from GitHub, testing, and building Docker images stored on DockerHub
- The team consisted of 4 developers; the IT organization consisted of 100+ people
- Knowit is one of the largest IT consulting groups in Northern Europe
- Technical environment: Java, Spring Framework, Spring Boot 2, CI/CD, CircleCI, IntelliJ IDEA, XML, JSON, AWS Cloud Formation, AWS EC2, AWS CloudWatch, AWS API Gateway, AWS ECS, AWS CLI, Angular 8, JSON, Apache Kafka, Microservices, Docker, Dockerhub, Scrum / Agile, Kanban, Git
Senior Performance Engineer
Net Entertainment AB / NetEnt AB
10.2012 - 08.2019
- Company Overview: As the Performance engineer at NetEnt Live Casino, it was my responsibility to maintain the performance and scalability of the video-streamed casino platform with live dealers
- In-depth analysis and profiling of the codebase to identify and eliminate performance bottlenecks
- Optimization of JVM settings, including Garbage Collection tuning, to improve system stability under high load
- Implementation and configuration of Kafka as a communication solution to ensure scalability and reliability of real-time data flows
- Performance testing and load tests to analyze the system's behavior under high load
- Close collaboration with the Operations Department to identify and resolve infrastructural issues and optimize the operating environment
- Analysis and improvement of network settings and system resources to ensure stable and efficient operation
- Continuous improvement of the system architecture in collaboration with developers, architects and operations
- Code review and refactoring with a focus on performance and maintenance
- My role required both technical analysis and close collaboration with operations to ensure a scalable and stable operation of the platform
- The team consisted of 10 people; the IT organization consisted of 150+ people
- As the Performance engineer at NetEnt Live Casino, it was my responsibility to maintain the performance and scalability of the video-streamed casino platform with live dealers
- Technical environment: Java EE, JAX-B, JAX-RS, JAX-WS, EJB, JPA, JTA, LIKE, JBoss EAP, Sun Solaris, Rabbit-MQ, Eclipse, PyDev, Apache Kafka, Red Hat, JBoss, ActiveMQ, Hibernate, MS-SQL, T-SQL, JSON, Groovy Script, Transaction Intensive System, Maven, Application Performance Monitoring, Jenkins, Mockito, XML, Junit, Linux, CI/CD, JIRA, Grinder/Jython, Scrum, Subversion, Git, GlassFish
Performance Engineer
Net Entertainment AB
08.2009 - 09.2012
- Company Overview: Net Entertainment was one of the world's largest providers of online gambling games and platforms, with high demands on transaction speed and performance
- Code and performance optimization: Analyzed and improved code and system settings for Net Entertainment's video slot platform
- Regulatory Adaptations: Ensured that custom adapters for regulated markets maintained a high level of gaming experience and performance
- Performance testing and scalability: Further developed and executed load tests to identify and resolve bottlenecks in a globally distributed gaming service with servers on multiple continents
- Build and Deployment Automation: Configured and set up a Jenkins-based build server from the ground up to improve development and deployment processes
- This work laid the foundation for future optimizations and scalability in NetEnt's platform and game engines
- Net Entertainment was one of the world's largest providers of online gambling games and platforms, with high demands on transaction speed and performance
- Technical environment: Java EE, JAX-B, JAX-RS, JAX-WS, EJB, JPA, JTA, LIKE, JBoss EAP, Linux, Sun Solaris, Apache Kafka, Red Hat, ActiveMQ, Hibernate, MS-SQL, T-SQL, JSON, Eclipse, Groovy Script, PyDev, Transaction Intensive System, Application Performance Monitoring, Jenkins, Mockito, Junit, Linux, CI/CD, JIRA, Grinder/Jython, Scrum, Subversion, Git, GlassFish
Senior System Developer / Management
Sigma AB
10.2008 - 08.2009
- Java, Spring, Cobol, System Architecture Design, MS-SQL, Transaction Intensive System, XML, Junit, Scrum, Kanban, Jira, Subversion
Senior System Developer
24 Poker / Entraction AB
03.2007 - 09.2008
- Java, Eclipse, JMeter, Perforce, Mercurial, XML, T-SQL, MS-SQL, P4, Git, Transaction Intensive System, Junit, JIRA, Scrum, Kanban.
Senior System Developer
Gimlet AB
02.2007 - 04.2007
- Java, Spring, Flex, ActionScript, Windows Platform, JIRA, Scrum, Kanban, Subversion, JUnit
Senior System Developer
Tain AB
02.2005 - 04.2007
- Java, Eclipse, Windows Platform, JUnit, T-SQL, MS-SQL, Server Analysis Services, Transaction Intensive System, JIRA, Scrum, XML, Subversion
Search Tools, System Developers
Spray Network Services
09.1999 - 12.2004
- Java, JSP, Java Servlets, Oracle, HTML, MySQL
Education
Bachelor of Science in Engineering -
Ronneby BTH
01.1997 - 01.1999
Bachelor's Degree - Electronics
Gävle Högskola
01.1993 - 01.1995
Skills
Java
Modern Java 17
Docker
Kubernetes
AWS
Azure
CI/CD
Kafka
REST
Python
Kibana
Agile
Scrum
Kanban
SAFe
Linux
JUnit
Spring Boot
Jakarta EE
IntelliJ
Maven
Gradle
Git
Python 2
Angular
SQL sentry
BDD
TDD
Javascript
Google Cloud Platform
JBoss
Oracle DB
PyDev
Grinder
Jython
Timeline
Senior System Developer
Handelsbanken IT
02.2023 - 12.2024
Senior System Developer
Worldline (formerly Bambora)
04.2021 - 02.2023
Senior System Developer
Bolagsverket
08.2020 - 04.2021
Senior System Developer
Knowit AB
08.2019 - 06.2020
Senior Performance Engineer
Net Entertainment AB / NetEnt AB
10.2012 - 08.2019
Performance Engineer
Net Entertainment AB
08.2009 - 09.2012
Senior System Developer / Management
Sigma AB
10.2008 - 08.2009
Senior System Developer
24 Poker / Entraction AB
03.2007 - 09.2008
Senior System Developer
Gimlet AB
02.2007 - 04.2007
Senior System Developer
Tain AB
02.2005 - 04.2007
Search Tools, System Developers
Spray Network Services
09.1999 - 12.2004
Bachelor of Science in Engineering -
Ronneby BTH
01.1997 - 01.1999
Bachelor's Degree - Electronics
Gävle Högskola
01.1993 - 01.1995