Java Backend

Job description

**Technical Stack (Must-Have Experience)** **Core Language & Framework** - **Java 17 - 25** working knowledge of modern features: records, sealed classes, pattern matching, virtual threads, structured concurrency, scoped values, string templates - **Spring Boot 3.x - 4.x** with **Spring WebFlux** (reactive/non-blocking) - **Project Reactor** Mono, Flux, reactive operators, error handling, timeout management - **MapStruct** for compile-time object mapping (or strong annotation processing understanding) **Microservices & Patterns** - Building and consuming **RESTful APIs** (OpenAPI-first development) - **Resilience4j** — circuit breakers, retry, timeout, bulkhead (or equivalent resilience library) - **WebClient** for non-blocking HTTP calls to upstream services - Service-to-service authentication (OAuth2 client credentials, token management) - **Caffeine** or similar caching solutions (understanding cache stampede, TTL strategies) - RFC 7807 Problem Details for error responses **Testing (Critical Requirement)** - **JUnit 5** with comprehensive unit testing - **WireMock** for HTTP service mocking in integration tests - **Testcontainers** for infrastructure-dependent testing - **Pact** consumer-driven contract testing (or strong willingness to learn immediately) - **Spring WebTestClient** for reactive endpoint testing - **StepVerifier** for testing reactive streams **Build & Quality** - **Gradle 8.x - 9.x** multi-module builds (Kotlin DSL awareness preferred) - **Checkstyle** for code style enforcement - **JaCoCo** for coverage reporting - **SonarQube** quality gate awareness - **OWASP Dependency Check** for vulnerability scanning **DevOps & CI/CD** - **GitLab CI** - Understanding of multi-stage pipelines: lint test security scan build deploy - **Docker** — writing Dockerfiles, multi-stage builds, non-root containers, image optimization - **Kubernetes (EKS)** — operational understanding of: - Deployments, Services, ConfigMaps, Secrets - Readiness/liveness probes and their impact on rolling updates - Horizontal Pod Autoscaler (HPA) - Resource requests and limits - Rolling deployments and rollback strategies - **Infrastructure as Code** awareness (Terraform, CDK, or Kustomize) - **External Secrets Operator** or equivalent secrets management (AWS Secrets Manager) **Observability & Monitoring** - **OpenTelemetry** for distributed tracing - **Micrometer** for application metrics - **Datadog** (or Prometheus/Grafana) for dashboards and alerting - Correlation ID propagation in reactive/non-thread-bound contexts - Understanding of SLOs, p95/p99 latency, error rate monitoring **Cloud (AWS)** - EKS (Kubernetes on AWS) - AWS Secrets Manager - Basic networking (VPC, security groups, service discovery within K8s) - ECR (container registry)