Senior Backend Java Developer

Senior Backend Java Developer – 12-Month Daily Rate Contract

Contract: 12 months

Working arrangement: Hybrid – 3 days per week onsite Dublin City Centre

We are recruiting a Senior Backend Java Developer to design and deliver enterprise applications and distributed services. This opportunity suits an experienced developer with strong Core Java skills and experience building secure APIs and event-driven systems.

Key Responsibilities

• Design, develop and maintain scalable Java applications and RESTful services.
• Build event-driven integrations using Apache Kafka and IBM MQ.
• Improve application performance, reliability and security.
• Develop database schemas, queries and persistence layers.
• Write automated tests and contribute to code reviews and engineering standards.
• Support containerised deployments and CI/CD pipelines.
• Collaborate with distributed teams throughout the software development lifecycle.

Key Requirements

• 10+ years’ experience designing and developing enterprise Java systems.
• Strong Core Java skills, with hands-on experience using Java 17 or 21, preferably Java 21.
• Experience with Spring, Spring Boot and Jakarta EE, ideally including Spring Framework 7 and Spring Boot 4.x.
• Knowledge of JVM internals, garbage collection tuning and performance profiling.
• Strong SQL and database experience with Oracle, PostgreSQL or MySQL, including PL/SQL where applicable.
• Experience with JPA/Hibernate, HikariCP and database migration tools such as Flyway or Liquibase.
• Experience with Kafka and IBM MQ, including partitioning, consumer groups, idempotency and transactional outbox patterns.
• Knowledge of Spring Security, OAuth2/OIDC, JWT and access controls.
• Experience designing APIs using OpenAPI/Swagger and implementing resilience patterns with Resilience4j.
• Strong automated testing skills using JUnit 5, Mockito, AssertJ, Testcontainers and contract testing tools.
• Experience with Docker, Kubernetes and/or Red Hat OpenShift.
• Familiarity with CI/CD tools such as Jenkins, GitHub Actions, GitLab CI or ArgoCD.
• Practical experience using AI-assisted development tools, such as Claude, GitHub Copilot, Devin or Cursor.
• Experience working within Agile teams and across the full SDLC.

Desirable Experience

• Redis, MongoDB or Elasticsearch.
• Micrometer, Prometheus, Grafana and OpenTelemetry.
• Spring AI, LLM integrations, RAG workflows or vector databases such as pgvector.