javademos/docs/14-lanes-21-to-25.md

14. The 21 to 25 lane: every claim in the hub posts, checked

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The two Java version guides on ankurm.com (features, upgrade guide) make about twenty checkable claims. scripts/lanes.sh checks each one on JDK 21, 25, 26 and 27, plus 23 and 24 (from the amazoncorretto:23 and :24 images) where the question is when something changed. The verdicts are below; the transcripts are the proof.

Claim	Verdict	Where it changed	Transcript
Records, pattern-matching switch, virtual threads, sequenced collections from the article run unchanged on 21, 25, 26, 27	true	final in 21	80
Scoped values are final in 25	true	preview in 21, final in 25 (JEP 506)	81
Structured concurrency is final in 25	false: still preview	5th preview in 25, 6th in 26, 7th in 27; --enable-preview is required on all three	82
Joiner.anySuccessfulResultOrThrow() (the article's code) works on 26 and 27	false: renamed	anySuccessfulOrThrow() from 26; allSuccessfulOrThrow() returns a List instead of a Stream from 26; a third type parameter arrives in 27	82, 89
Finalization is removed by default	false: still on	finalize() still runs on 21, 25, 26 and 27 unless you pass --finalization=disabled	83
System.setSecurityManager() throws UnsupportedOperationException	true	already on 21 by default; permanent from 24 (JEP 486)	84
Thread.stop, suspend and resume are removed	half true	suspend/resume compile on 21 and do not compile on 23, 24, 25 or 26; stop() still compiles on 25 and throws; removed in 26	85, 73
sun.misc.Unsafe memory methods warn	true from 24	none on 21, warning on 24 and 25 (JEP 498)	86
JNI use warns by default	true from 24	none on 21, warning on 24 and 25 (JEP 472)	86
Virtual threads pin their carrier inside synchronized on "Java 21 to 24"	false: 21 to 23	pinned on 21 and 23, not pinned on 24, 25, 26, 27 (JEP 491)	87
"Java 25 ships an improved generational ZGC mode"	misleading	generational is the only ZGC from 24; -XX:-ZGenerational is ignored with a warning on 24 and 25 and rejected on 26 and 27	88
Reflection writing to a final field warns from 26	true	silent on 25, warns on 26 and 27 (JEP 500)	70, 91
Unnamed patterns and unnamed classes are final in 25	half true	the underscore was final in 22 (JEP 456); compact source files with instance main() (JEP 512) are final in 25	90

Build-file claims (--release, Gradle, Lombok, Mockito, annotation processing, jdeps) are checked in chapter 15.

Claims about other projects came from their own pages, read on 2026-09-21, not from a run:

Claim	Verdict	Source
Spring Boot 3.4 is the first with official Java 25 support	false	Spring Boot 3.4.x is documented up to Java 24, 3.5.x up to Java 25, 4.1.1 up to Java 26 (system requirements); 27 is not listed yet
Lombok 1.18.34 or later works on Java 25	false	JDK 25 support arrived in 1.18.40 (2025-09-04), JDK 26 in 1.18.46, JDK 27 in 1.18.48 (changelog); a run confirms 1.18.34 fails on 25 (95, chapter 15)
Mockito 5.12 or later is enough for Java 25	false (run)	5.12.0 and 5.17.0 cannot mock an interface on 25 or 27; 5.18.0 is the first that can (97, chapter 15)
Hibernate 7 requires Jakarta EE 10	false	Hibernate ORM 7.0 requires Jakarta Persistence 3.2 (Jakarta EE 11) (release page)

The next chapter is 15, the build-file half; 12 carries the lane table forward to 29.

prompts/ holds the thirteen AI prompts from the two posts, one per file, corrected to match this chapter.

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