Solon
Java enterprise application development framework
...It advertises large concurrency gains, lower memory use, much faster startup, and dramatically smaller packages while remaining compatible from Java 8 through Java 24. The framework focuses on restrained APIs and an open ecosystem, with modules that cover web, data, cloud, and microservice patterns. Its messaging emphasizes “replaceable Spring” ergonomics—keeping developer familiarity while reducing overhead and improving deployment characteristics. Releases and companion repositories present an active community and production-oriented guidance. The broader Solon org also maintains AI/agent extensions (e.g., MCP components) that complement application development.