Modernize Java with Cursor and GitLab

"Modernize Java 8 to Java 21" sounds like one task. It is not. It touches the build, the runtime, dependencies, APIs, concurrency, tests, containers, and production behavior, often all at once. Ask an agent to do all of that in one prompt, and you get one enormous merge request that nobody can safely review. Cursor, an AI coding agent, is good at the focused part of that problem. Give it one failing test or one bounded issue, and it can inspect the implementation, explain what