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
