Java Developer @ j-labs software specialist

• Minimum 4 years of commercial experience in developing backend applications in Java.
• Very good knowledge of Java and Spring Boot.
• Experience in designing and developing backend applications.
• Experience in system integration and working with legacy systems.
• Experience in analyzing and solving concurrency-related problems.
• Experience in optimizing application performance and solving performance issues.
• Experience working with databases, especially Oracle/PL/SQL.
• Experience working with distributed environments and microservice architecture.
• Practical knowledge of CI/CD and working with applications deployed in containerized environments.
• Knowledge of English at a minimum of B2 level.
• Knowledge of Polish at a minimum of B2 level.

• You will join a team developing and modernizing a platform supporting investment fund management processes.
• The project involves the gradual migration of an existing system to a new solution based on Java and Spring Boot. We work in stages — currently, a POC is being implemented, covering a new backend with an adapter to the legacy system, and in subsequent stages, business logic will be progressively moved to the new solution.
• As part of the project, new functionalities are also being developed, and existing solutions are gradually being modernized and adapted to the new architecture. New components are verified for correctness, security, scalability, and performance.
• The work covers the entire software development lifecycle — from analysis and design of solutions, through implementation and testing, to integration with systems and deployment.
• An important element of the project is building a new version of the system, not just maintaining the existing solution. The team has a real impact on the shape of the created solutions — from their design and proposals to practical verification, including performance, scalability, and correctness.
• On a daily basis, you will work with, among others, Java 21, Spring Boot, Gradle 8, PL/SQL/Oracle, Liquibase, Spock, OpenAPI Generator, OpenShift, Jenkins, Bitbucket, SonarQube, UNIX/Linux, Bash, Jira, Confluence, Red Hat Data Grid/Infinispan, and TCP/Sockets.
• The project is long-term and assumes further stages of platform development and modernization, offering the opportunity to work on both new solutions and demanding aspects of transforming the existing system.
• Location: Krakow, hybrid work (2 days a week from the office).

Why it's worth it?

• Long-term project involving a multi-stage modernization of a large platform.
• Real impact on the shape of the new architecture — from designing and proposing solutions to their practical verification.
• Complex backend issues beyond creating Spring Boot endpoints — including concurrency, synchronization, session and connection management, and handling parallel requests.
• Work in a distributed environment — OpenShift, multiple application instances, scaling, and diagnosing problems.
• Development beyond just Java — independently creating and developing Jenkins pipelines and participating in deployments on OpenShift, with the opportunity to gain practical experience in CI/CD and automation.

,[Backend development in Java / Spring Boot and gradual migration and modernization of existing functionalities., Creating adapters and integrating the new solution with the existing system., Gradual transfer of business logic to the new architecture., Solving concurrency-related problems — handling parallel requests, synchronizing access to sessions and connections, and ensuring correct operation execution., Solving problems related to application operation in a distributed and multi-instance OpenShift environment., Ensuring application scalability and proper traffic routing between instances., Performance tuning — application profiling, load testing, optimizing communication with the old backend, and optimizing application and JVM performance., Creating unit and component tests., Creating and developing Jenkins pipelines and participating in deployments on OpenShift., Independent analysis and solving problems arising in environments., Collaboration with the QA team, frontend developer, and other individuals involved in the project.]