Spring Boot auto-configuration, starters, and production-ready Java services.
Slow JVM cold start breaks scale-to-zero and autoscaling. Three ways to fix it in 2026 — Project Leyden's AOT cache, GraalVM Native Image, and CRaC — with the exact commands, the trade-offs, and a decision framework.
Write tests that catch real bugs: JUnit 5 lifecycle, parameterized tests, Mockito, WireMock, Testcontainers, and mutation testing.
SOLID beyond theory: real production anti-patterns, Spring Boot refactorings, and the design constraints that prevent codebase rot.
Production REST APIs with Spring Boot: JPA, Bean Validation, global exception handling, MockMvc testing, and scalable patterns.
Spring AI 1.1 deep-dive: production RAG pipeline with PII scrubbing, circuit breakers, Micrometer observability, and answer evaluation.
Java 21 virtual threads: M:N scheduling, pinning hazards, ThreadLocal pitfalls, JFR detection, and what migration really takes.
From 5-second Spring Boot cold starts to 50ms with GraalVM native images. The real gotchas, wins, and whether it's worth it.
An honest Go (Gin) vs. Java (Spring Boot) comparison for backend services in 2026: memory behavior, cold starts, GC pauses, and cost math — built on documented runtime behavior plus a copy-paste benchmark harness, not unverifiable numbers.