JDK 25 Upgrade Blocker Lint

It reads your .java files and flags the calls JDK 21 and JDK 25 removed, disabled or refuse to run: Security Manager, AccessController.doPrivileged, sun.misc.Unsafe, javax.* Jakarta imports, the Applet API, Thread.stop, finalize and more. 18 rules; the bundled 64-line fixture returns 23 findings, 15 errors and 8 warnings, each with its line, its JEP and the replacement call.

Java teams moving a Spring Boot 2 or Jakarta EE service off Java 17 onto JDK 21 or the JDK 25 LTS, and the platform engineer who owns that upgrade ticket. If your repository still compiles on 17 but nobody has read every file for removed APIs, this reads them in one pass.

javac prints a deprecation warning and then produces a working class file, so the build stays green and the UnsupportedOperationException arrives in production instead. AI assistants trained on older Java keep emitting javax.persistence imports and setSecurityManager calls, so the problem reappears in code written this week.

Free, forever: the file you have open, all 18 rules, no key and no cap — that reading job finishes on its own. The key covers the other job: sweeping every .java file in the workspace and writing one dated migration report file with every blocker, JEP and replacement. That sweep runs free for seven days first, then $29 once.

A Java migration consultant bills $120 to $200 an hour, and a two-day audit of a single repository runs past $2,000. Reading one service by hand takes an afternoon and misses the quiet ones, because a javax.servlet import looks correct until the Jakarta runtime silently skips the bean.