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
@@ -0,0 +1,33 @@
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.StructuredTaskScope.Joiner;
+
+/** Five tasks that sleep a random time and fail if they were "too slow". Seeded, so the transcript is repeatable. */
+public class RandomTasks {
+
+    static class TooSlowException extends Exception {
+        TooSlowException(String m) { super(m); }
+    }
+
+    public static void main(String[] args) throws Exception {
+        long seed = Long.parseLong(args[0]);
+        int threshold = 700;
+        Random random = new Random(seed);
+        List<Callable<Integer>> tasks = new ArrayList<>();
+        for (int i = 0; i < 5; i++) {
+            int duration = random.nextInt(1000);
+            System.out.println("Duration: " + duration);
+            tasks.add(() -> {
+                Thread.sleep(duration);
+                if (duration > threshold) throw new TooSlowException("Duration " + duration + " greater than threshold " + threshold);
+                return duration;
+            });
+        }
+        try (var scope = StructuredTaskScope.open(Joiner.<Integer>allSuccessfulOrThrow())) {
+            tasks.forEach(scope::fork);
+            for (int r : scope.join()) System.out.println("Result: " + r);
+        } catch (ExecutionException e) {
+            System.out.println("ExecutionException: " + e.getCause().getClass().getSimpleName() + ": " + e.getCause().getMessage());
+        }
+    }
+}