Add structured-concurrency-final module: StructuredTaskScope final in JDK 28 (JEP 543), run on 28-ea, 27, 26 and 25

Runnable demos for the ankurm.com structured-concurrency-java article: the ExecutorService thread leak and its fix, every built-in Joiner, structure violations, timeouts, a custom Joiner, JSON thread dumps (in-process and jcmd), scoped values, javap diffs of the API on 25, 26, 27 and 28-ea, compiler output for six pieces of 25/26-era code, and the preview class-file trap between 27 and 28. Transcripts in output/. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01CifR2BE7PBvRy5hT8TS9oz
2026-10-26 02:01:31 +00:00
parent 2e25042a68
commit c93a1fffbb
37 changed files with 1351 additions and 0 deletions
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+$ javac src/Failures.java && java Failures     (28-beta+21-ea)
+-- Subtask.get() before join()
+  java.lang.IllegalStateException: null
+-- leaving the try block without join()
+  java.lang.IllegalStateException: Owner did not join after forking
+-- fork() from a thread that does not own the scope
+  returned java.lang.WrongThreadException: Current thread not owner
+-- closing scopes out of order (not try-with-resources)
+  java.util.concurrent.StructureViolationException: null
+-- join() twice
+  java.lang.IllegalStateException: Already joined or scope is closed
+-- the failure surfaces as ExecutionException; pattern-match the cause
+  I/O failed: disk gone
+-- two subtasks fail: which cause do you get?
+  cause = first   (the first to fail wins)