Doświadczenie w pracy:
Language: Java 8, Java 21 (participated in migration)
Spring Boot (MVC, Data, Security, Cloud), Hibernate, MyBatis, Lombok, MapStruct, Feign Client, Apache Kafka, Outbox pattern
Databases: PostgreSQL (complex SQL queries, optimization, writing functions, working with VIEWs, REF CURSORs)
Designed and implemented a PL/pgSQL function in PostgreSQL for atomic counter numbering updates at the beginning of the fiscal year. The solution completely eliminated the risks of incorrect data, which could have led to legal and financial consequences for the company.
Conducted a comprehensive optimization of the data filtering system for the main system entity. As a result, the average query execution time decreased by 1 second, and the database load was reduced.
Identified and eliminated an architectural inefficiency in accessing one of the key entities. After refactoring, the daily database load decreased by approximately 7 million queries, which significantly improved the overall system responsiveness.
Designed and implemented an automatic restart mechanism for the background task system based on Kafka. The mechanism guarantees data processing continuity even during emergency application shutdowns, minimizing the need for manual intervention.
Actively participated in the project migration from Java 8 to Java 21: conducted module analysis, refactored legacy code taking into account new language features and deprecated APIs, ensured test coverage. The work made it possible to use modern language features and update dependencies.
Constantly engaged in refactoring legacy code (5+ years old), improving its readability, testability, and performance. Worked with issues such as excessive coupling, code duplication, and suboptimal algorithms.
Umiejętności zawodowe i inne:
Spring Boot (MVC, Data, Security, Cloud), Hibernate, MyBatis, Lombok, MapStruct, Feign Client, Apache Kafka, Outbox pattern
Databases: PostgreSQL (complex SQL queries, optimization, writing functions, working with VIEWs, REF CURSORs)
