The two pillars of requirements

It’s Friday afternoon, 4:00 p.m. You’ve just merged the feature, the pipeline is green, and you feel invincible. Then the Slack message comes from the product owner: “Hey, looks good, but why does X happen when I do Y? That was discussed completely …

The year is 2025. Spring Boot 4 is here, and we no longer use deprecated RestTemplate calls. We combine the new Declarative HTTP Client feature with the proven Circuit Breaker Pattern and refine it with a Retry strategy.

If you’ve been programming Java for a while, you probably use List, Set, and Map every day. But let’s be honest: most developers barely scratch the surface of what the Java Collections API can really do.