8246585: ForkJoin updates

8229253: forkjoin/FJExceptionTableLeak.java fails "AssertionError: failed to satisfy condition"

Reviewed-by: dl

src/java.base/share/classes/java/util/concurrent/CountedCompleter.java

@@ -357,7 +357,7 @@ import java.lang.invoke.VarHandle;
  * within this method to ensure thread safety of accesses to fields of
  * this task or other completed tasks.
  *
- * <p><b>Completion Traversals</b>. If using {@code onCompletion} to
+ * <p><b>Completion Traversals.</b> If using {@code onCompletion} to
  * process completions is inapplicable or inconvenient, you can use
  * methods {@link #firstComplete} and {@link #nextComplete} to create
  * custom traversals.  For example, to define a MapReducer that only
@@ -553,6 +553,11 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
         return PENDING.compareAndSet(this, expected, count);
     }
 
+    // internal-only weak version
+    final boolean weakCompareAndSetPendingCount(int expected, int count) {
+        return PENDING.weakCompareAndSet(this, expected, count);
+    }
+
     /**
      * If the pending count is nonzero, (atomically) decrements it.
      *
@@ -562,7 +567,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
     public final int decrementPendingCountUnlessZero() {
         int c;
         do {} while ((c = pending) != 0 &&
-                     !PENDING.weakCompareAndSet(this, c, c - 1));
+                     !weakCompareAndSetPendingCount(c, c - 1));
         return c;
     }
 
@@ -595,7 +600,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
                     return;
                 }
             }
-            else if (PENDING.weakCompareAndSet(a, c, c - 1))
+            else if (a.weakCompareAndSetPendingCount(c, c - 1))
                 return;
         }
     }
@@ -618,7 +623,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
                     return;
                 }
             }
-            else if (PENDING.weakCompareAndSet(a, c, c - 1))
+            else if (a.weakCompareAndSetPendingCount(c, c - 1))
                 return;
         }
     }
@@ -663,7 +668,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
         for (int c;;) {
             if ((c = pending) == 0)
                 return this;
-            else if (PENDING.weakCompareAndSet(this, c, c - 1))
+            else if (weakCompareAndSetPendingCount(c, c - 1))
                 return null;
         }
     }
@@ -718,30 +723,33 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      *                 processed.
      */
     public final void helpComplete(int maxTasks) {
-        Thread t; ForkJoinWorkerThread wt;
+        ForkJoinPool.WorkQueue q; Thread t; boolean owned;
-        if (maxTasks > 0 && status >= 0) {
+        if (owned = (t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
-            if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
+            q = ((ForkJoinWorkerThread)t).workQueue;
-                (wt = (ForkJoinWorkerThread)t).pool.
+        else
-                    helpComplete(wt.workQueue, this, maxTasks);
+            q = ForkJoinPool.commonQueue();
-            else
+        if (q != null && maxTasks > 0)
-                ForkJoinPool.common.externalHelpComplete(this, maxTasks);
+            q.helpComplete(this, owned, maxTasks);
-        }
     }
 
+    // ForkJoinTask overrides
+
     /**
      * Supports ForkJoinTask exception propagation.
      */
-    void internalPropagateException(Throwable ex) {
+    @Override
-        CountedCompleter<?> a = this, s = a;
+    final int trySetException(Throwable ex) {
-        while (a.onExceptionalCompletion(ex, s) &&
+        CountedCompleter<?> a = this, p = a;
-               (a = (s = a).completer) != null && a.status >= 0 &&
+        do {} while (isExceptionalStatus(a.trySetThrown(ex)) &&
-               isExceptionalStatus(a.recordExceptionalCompletion(ex)))
+                     a.onExceptionalCompletion(ex, p) &&
-            ;
+                     (a = (p = a).completer) != null && a.status >= 0);
+        return status;
     }
 
     /**
      * Implements execution conventions for CountedCompleters.
      */
+    @Override
     protected final boolean exec() {
         compute();
         return false;
@@ -756,6 +764,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      *
      * @return the result of the computation
      */
+    @Override
     public T getRawResult() { return null; }
 
     /**
@@ -765,6 +774,7 @@ public abstract class CountedCompleter<T> extends ForkJoinTask<T> {
      * overridden to update existing objects or fields, then it must
      * in general be defined to be thread-safe.
      */
+    @Override
     protected void setRawResult(T t) { }
 
     // VarHandle mechanics

src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java

@@ -35,10 +35,8 @@
 
 package java.util.concurrent;
 
-import java.security.AccessControlContext;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
-import java.security.ProtectionDomain;
 
 /**
  * A thread managed by a {@link ForkJoinPool}, which executes
@@ -62,26 +60,38 @@ public class ForkJoinWorkerThread extends Thread {
      * ForkJoinTasks. For explanation, see the internal documentation
      * of class ForkJoinPool.
      *
-     * This class just maintains links to its pool and WorkQueue.  The
+     * This class just maintains links to its pool and WorkQueue.
-     * pool field is set immediately upon construction, but the
-     * workQueue field is not set until a call to registerWorker
-     * completes. This leads to a visibility race, that is tolerated
-     * by requiring that the workQueue field is only accessed by the
-     * owning thread.
-     *
-     * Support for (non-public) subclass InnocuousForkJoinWorkerThread
-     * requires that we break quite a lot of encapsulation (via helper
-     * methods in ThreadLocalRandom) both here and in the subclass to
-     * access and set Thread fields.
      */
 
     final ForkJoinPool pool;                // the pool this thread works in
     final ForkJoinPool.WorkQueue workQueue; // work-stealing mechanics
 
-    /** An AccessControlContext supporting no privileges */
+    /**
-    private static final AccessControlContext INNOCUOUS_ACC =
+     * Full nonpublic constructor.
-        new AccessControlContext(
+     */
-            new ProtectionDomain[] { new ProtectionDomain(null, null) });
+    ForkJoinWorkerThread(ThreadGroup group, ForkJoinPool pool,
+                         boolean useSystemClassLoader, boolean isInnocuous) {
+        super(group, null, pool.nextWorkerThreadName(), 0L);
+        UncaughtExceptionHandler handler = (this.pool = pool).ueh;
+        this.workQueue = new ForkJoinPool.WorkQueue(this, isInnocuous);
+        super.setDaemon(true);
+        if (handler != null)
+            super.setUncaughtExceptionHandler(handler);
+        if (useSystemClassLoader)
+            super.setContextClassLoader(ClassLoader.getSystemClassLoader());
+    }
+
+    /**
+     * Creates a ForkJoinWorkerThread operating in the given thread group and
+     * pool.
+     *
+     * @param group if non-null, the thread group for this thread
+     * @param pool the pool this thread works in
+     * @throws NullPointerException if pool is null
+     */
+    /* TODO: protected */ ForkJoinWorkerThread(ThreadGroup group, ForkJoinPool pool) {
+        this(group, pool, false, false);
+    }
 
     /**
      * Creates a ForkJoinWorkerThread operating in the given pool.
@@ -90,38 +100,7 @@ public class ForkJoinWorkerThread extends Thread {
      * @throws NullPointerException if pool is null
      */
     protected ForkJoinWorkerThread(ForkJoinPool pool) {
-        // Use a placeholder until a useful name can be set in registerWorker
+        this(null, pool, false, false);
-        super("aForkJoinWorkerThread");
-        this.pool = pool;
-        this.workQueue = pool.registerWorker(this);
-    }
-
-    /**
-     * Version for use by the default pool.  Supports setting the
-     * context class loader.  This is a separate constructor to avoid
-     * affecting the protected constructor.
-     */
-    ForkJoinWorkerThread(ForkJoinPool pool, ClassLoader ccl) {
-        super("aForkJoinWorkerThread");
-        super.setContextClassLoader(ccl);
-        ThreadLocalRandom.setInheritedAccessControlContext(this, INNOCUOUS_ACC);
-        this.pool = pool;
-        this.workQueue = pool.registerWorker(this);
-    }
-
-    /**
-     * Version for InnocuousForkJoinWorkerThread.
-     */
-    ForkJoinWorkerThread(ForkJoinPool pool,
-                         ClassLoader ccl,
-                         ThreadGroup threadGroup,
-                         AccessControlContext acc) {
-        super(threadGroup, null, "aForkJoinWorkerThread");
-        super.setContextClassLoader(ccl);
-        ThreadLocalRandom.setInheritedAccessControlContext(this, acc);
-        ThreadLocalRandom.eraseThreadLocals(this); // clear before registering
-        this.pool = pool;
-        this.workQueue = pool.registerWorker(this);
     }
 
     /**
@@ -176,11 +155,14 @@ public class ForkJoinWorkerThread extends Thread {
      * {@link ForkJoinTask}s.
      */
     public void run() {
-        if (workQueue.array == null) { // only run once
+        Throwable exception = null;
-            Throwable exception = null;
+        ForkJoinPool p = pool;
+        ForkJoinPool.WorkQueue w = workQueue;
+        if (p != null && w != null) {   // skip on failed initialization
             try {
+                p.registerWorker(w);
                 onStart();
-                pool.runWorker(workQueue);
+                p.runWorker(w);
             } catch (Throwable ex) {
                 exception = ex;
             } finally {
@@ -190,18 +172,12 @@ public class ForkJoinWorkerThread extends Thread {
                     if (exception == null)
                         exception = ex;
                 } finally {
-                    pool.deregisterWorker(this, exception);
+                    p.deregisterWorker(this, exception);
                 }
             }
         }
     }
 
-    /**
-     * Non-public hook method for InnocuousForkJoinWorkerThread.
-     */
-    void afterTopLevelExec() {
-    }
-
     /**
      * A worker thread that has no permissions, is not a member of any
      * user-defined ThreadGroup, uses the system class loader as
@@ -221,15 +197,7 @@ public class ForkJoinWorkerThread extends Thread {
                 }});
 
         InnocuousForkJoinWorkerThread(ForkJoinPool pool) {
-            super(pool,
+            super(innocuousThreadGroup, pool, true, true);
-                  ClassLoader.getSystemClassLoader(),
-                  innocuousThreadGroup,
-                  INNOCUOUS_ACC);
-        }
-
-        @Override // to erase ThreadLocals
-        void afterTopLevelExec() {
-            ThreadLocalRandom.eraseThreadLocals(this);
         }
 
         @Override // to silently fail

test/jdk/java/util/concurrent/forkjoin/AsyncShutdownNow.java

@@ -0,0 +1,177 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @run testng AsyncShutdownNow
+ * @summary Test invoking shutdownNow with threads blocked in Future.get,
+ *          invokeAll, and invokeAny
+ */
+
+// TODO: this test is far too slow
+
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.testng.annotations.AfterClass;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class AsyncShutdownNow {
+
+    // long running interruptible task
+    private static final Callable<Void> SLEEP_FOR_A_DAY = () -> {
+        Thread.sleep(86400_000);
+        return null;
+    };
+
+    private ScheduledExecutorService scheduledExecutor;
+
+    @BeforeClass
+    public void setup() {
+        scheduledExecutor = Executors.newScheduledThreadPool(1);
+    }
+
+    @AfterClass
+    public void teardown() {
+        scheduledExecutor.shutdown();
+    }
+
+    /**
+     * Schedule the given executor service to be shutdown abruptly after the given
+     * delay, in seconds.
+     */
+    private void scheduleShutdownNow(ExecutorService executor, int delayInSeconds) {
+        scheduledExecutor.schedule(() -> {
+            executor.shutdownNow();
+            return null;
+        }, delayInSeconds, TimeUnit.SECONDS);
+    }
+
+    /**
+     * The executors to test.
+     */
+    @DataProvider(name = "executors")
+    public Object[][] executors() {
+        return new Object[][] {
+                { new ForkJoinPool() },
+                { new ForkJoinPool(1) },
+        };
+    }
+
+    /**
+     * Test shutdownNow with running task and thread blocked in Future::get.
+     */
+    @Test(dataProvider = "executors")
+    public void testFutureGet(ExecutorService executor) throws Exception {
+        System.out.format("testFutureGet: %s%n", executor);
+        scheduleShutdownNow(executor, 5);
+        try {
+            // submit long running task, the task should be cancelled
+            Future<?> future = executor.submit(SLEEP_FOR_A_DAY);
+            try {
+                future.get();
+                assertTrue(false);
+            } catch (ExecutionException e) {
+                // expected
+            }
+        } finally {
+            executor.shutdown();
+        }
+    }
+
+    /**
+     * Test shutdownNow with running task and thread blocked in a timed Future::get.
+     */
+    @Test(dataProvider = "executors")
+    public void testTimedFutureGet(ExecutorService executor) throws Exception {
+        System.out.format("testTimedFutureGet: %s%n", executor);
+        scheduleShutdownNow(executor, 5);
+        try {
+            // submit long running task, the task should be cancelled
+            Future<?> future = executor.submit(SLEEP_FOR_A_DAY);
+            try {
+                future.get(1, TimeUnit.HOURS);
+                assertTrue(false);
+            } catch (ExecutionException e) {
+                // expected
+            }
+        } finally {
+            executor.shutdown();
+        }
+    }
+
+    /**
+     * Test shutdownNow with thread blocked in invokeAll.
+     */
+    @Test(dataProvider = "executors")
+    public void testInvokeAll(ExecutorService executor) throws Exception {
+        System.out.format("testInvokeAll: %s%n", executor);
+        scheduleShutdownNow(executor, 5);
+        try {
+            // execute long running tasks
+            List<Future<Void>> futures = executor.invokeAll(List.of(SLEEP_FOR_A_DAY, SLEEP_FOR_A_DAY));
+            for (Future<Void> f : futures) {
+                assertTrue(f.isDone());
+                try {
+                    Object result = f.get();
+                    assertTrue(false);
+                } catch (ExecutionException | CancellationException e) {
+                    // expected
+                }
+            }
+        } finally {
+            executor.shutdown();
+        }
+    }
+
+    /**
+     * Test shutdownNow with thread blocked in invokeAny.
+     */
+    @Test(dataProvider = "executors")
+    public void testInvokeAny(ExecutorService executor) throws Exception {
+        System.out.format("testInvokeAny: %s%n", executor);
+        scheduleShutdownNow(executor, 5);
+        try {
+            try {
+                // execute long running tasks
+                executor.invokeAny(List.of(SLEEP_FOR_A_DAY, SLEEP_FOR_A_DAY));
+                assertTrue(false);
+            } catch (ExecutionException e) {
+                // expected
+            }
+        } finally {
+            executor.shutdown();
+        }
+    }
+}

test/jdk/java/util/concurrent/forkjoin/AsyncShutdownNowInvokeAny.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @run testng AsyncShutdownNowInvokeAny
+ * @summary A variant of AsyncShutdownNow useful for race bug hunting
+ */
+
+// TODO: reorganize all of the AsyncShutdown tests
+
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.testng.annotations.AfterClass;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class AsyncShutdownNowInvokeAny {
+
+    // long running interruptible task
+    private static final Callable<Void> SLEEP_FOR_A_DAY = () -> {
+        Thread.sleep(86400_000);
+        return null;
+    };
+
+    private ScheduledExecutorService scheduledExecutor;
+
+    @BeforeClass
+    public void setup() {
+        scheduledExecutor = Executors.newScheduledThreadPool(1);
+    }
+
+    @AfterClass
+    public void teardown() {
+        scheduledExecutor.shutdown();
+    }
+
+    /**
+     * Schedule the given executor service to be shutdown abruptly after the given
+     * delay, in seconds.
+     */
+    private void scheduleShutdownNow(ExecutorService executor, int delayInSeconds) {
+        scheduledExecutor.schedule(() -> {
+            executor.shutdownNow();
+            return null;
+        }, delayInSeconds, TimeUnit.SECONDS);
+    }
+
+    /**
+     * Test shutdownNow with thread blocked in invokeAny.
+     */
+    @Test
+    public void testInvokeAny() throws Exception {
+        final int reps = 4;
+        for (int rep = 1; rep < reps; rep++) {
+            ExecutorService pool = new ForkJoinPool(1);
+            scheduleShutdownNow(pool, 5);
+            try {
+                try {
+                    // execute long running tasks
+                    pool.invokeAny(List.of(SLEEP_FOR_A_DAY, SLEEP_FOR_A_DAY));
+                    assertTrue(false);
+                } catch (ExecutionException e) {
+                    // expected
+                }
+            } finally {
+                pool.shutdown();
+            }
+        }
+    }
+}

test/jdk/java/util/concurrent/forkjoin/AsyncShutdownNowInvokeAnyRace.java

@@ -0,0 +1,199 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @run testng AsyncShutdownNowInvokeAnyRace
+ * @summary A variant of AsyncShutdownNow useful for race bug hunting
+ */
+
+// TODO: reorganize all of the AsyncShutdown tests
+
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.Future;
+import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.LockInfo;
+import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
+
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class AsyncShutdownNowInvokeAnyRace {
+
+    // TODO: even more jitter-inducing parallelism?
+
+//         int nThreads = ThreadLocalRandom.current().nextInt(1, 50);
+//         ExecutorService pool = Executors.newCachedThreadPool();
+//         Callable<Void> task = () -> { testInvokeAny_1(); return null; };
+//         List<Callable<Void>> tasks = Collections.nCopies(nThreads, task);
+//         try {
+//             for (Future<Void> future : pool.invokeAll(tasks)) {
+//                 future.get();
+//             }
+//         } finally {
+//             pool.shutdown();
+//         }
+//     }
+
+//     public void testInvokeAny_1() throws Exception {
+
+    /**
+     * Test shutdownNow with thread blocked in invokeAny.
+     */
+    @Test
+    public void testInvokeAny() throws Exception {
+        final int reps = 30_000;
+        ThreadLocalRandom rnd = ThreadLocalRandom.current();
+        int falseAlarms = 0;
+        for (int rep = 1; rep < reps; rep++) {
+            ForkJoinPool pool = new ForkJoinPool(1);
+            CountDownLatch pleaseShutdownNow = new CountDownLatch(1);
+            int nTasks = rnd.nextInt(2, 5);
+            AtomicInteger threadsStarted = new AtomicInteger(0);
+            AtomicReference<String> poolAtShutdownNow = new AtomicReference<>();
+            Callable<Void> blockPool = () -> {
+                threadsStarted.getAndIncrement();
+                // await submission quiescence; may false-alarm
+                // TODO: consider re-checking to reduce false alarms
+                while (threadsStarted.get() + pool.getQueuedSubmissionCount() < nTasks)
+                    Thread.yield();
+                pleaseShutdownNow.countDown();
+                Thread.sleep(86400_000);
+                return null;
+            };
+            List<Callable<Void>> tasks = Collections.nCopies(nTasks, blockPool);
+            Runnable shutdown = () -> {
+                try {
+                    pleaseShutdownNow.await();
+                    poolAtShutdownNow.set(pool.toString());
+                    pool.shutdownNow();
+                } catch (Throwable t) { throw new AssertionError(t); }
+            };
+            Future<Void> shutdownResult = CompletableFuture.runAsync(shutdown);
+            try {
+                try {
+                    if (rnd.nextBoolean())
+                        pool.invokeAny(tasks, 10L, SECONDS);
+                    else
+                        pool.invokeAny(tasks);
+                    throw new AssertionError("should throw");
+                } catch (RejectedExecutionException re) {
+                    falseAlarms++;
+                } catch (CancellationException re) {
+                } catch (ExecutionException ex) {
+                    Throwable cause = ex.getCause();
+                    if (!(cause instanceof InterruptedException) &&
+                        !(cause instanceof CancellationException))
+                        throw ex;
+                } catch (TimeoutException ex) {
+                    dumpTestThreads();
+                    int i = rep;
+                    String detail = String.format(
+                        "invokeAny timed out, "
+                        + "nTasks=%d rep=%d threadsStarted=%d%n"
+                        + "poolAtShutdownNow=%s%n"
+                        + "poolAtTimeout=%s%n"
+                        + "queuedTaskCount=%d queuedSubmissionCount=%d",
+                        nTasks, i, threadsStarted.get(),
+                        poolAtShutdownNow,
+                        pool,
+                        pool.getQueuedTaskCount(),
+                        pool.getQueuedSubmissionCount());
+                    throw new AssertionError(detail, ex);
+                }
+            } finally {
+                pool.shutdown();
+            }
+            if (falseAlarms != 0)
+                System.out.println("Premature shutdowns = " + falseAlarms);
+            shutdownResult.get();
+        }
+    }
+
+    //--- thread stack dumping (from JSR166TestCase.java) ---
+
+    private static final ThreadMXBean THREAD_MXBEAN
+        = ManagementFactory.getThreadMXBean();
+
+    /** Returns true if thread info might be useful in a thread dump. */
+    static boolean threadOfInterest(ThreadInfo info) {
+        final String name = info.getThreadName();
+        String lockName;
+        if (name == null)
+            return true;
+        if (name.equals("Signal Dispatcher")
+            || name.equals("WedgedTestDetector"))
+            return false;
+        if (name.equals("Reference Handler")) {
+            // Reference Handler stacktrace changed in JDK-8156500
+            StackTraceElement[] stackTrace; String methodName;
+            if ((stackTrace = info.getStackTrace()) != null
+                && stackTrace.length > 0
+                && (methodName = stackTrace[0].getMethodName()) != null
+                && methodName.equals("waitForReferencePendingList"))
+                return false;
+            // jdk8 Reference Handler stacktrace
+            if ((lockName = info.getLockName()) != null
+                && lockName.startsWith("java.lang.ref"))
+                return false;
+        }
+        if ((name.equals("Finalizer") || name.equals("Common-Cleaner"))
+            && (lockName = info.getLockName()) != null
+            && lockName.startsWith("java.lang.ref"))
+            return false;
+        if (name.startsWith("ForkJoinPool.commonPool-worker")
+            && (lockName = info.getLockName()) != null
+            && lockName.startsWith("java.util.concurrent.ForkJoinPool"))
+            return false;
+        return true;
+    }
+
+    /**
+     * A debugging tool to print stack traces of most threads, as jstack does.
+     * Uninteresting threads are filtered out.
+     */
+    static void dumpTestThreads() {
+        System.err.println("------ stacktrace dump start ------");
+        for (ThreadInfo info : THREAD_MXBEAN.dumpAllThreads(true, true))
+            if (threadOfInterest(info))
+                System.err.print(info);
+        System.err.println("------ stacktrace dump end ------");
+    }
+
+}

test/jdk/java/util/concurrent/forkjoin/FJExceptionTableLeak.java

@@ -1,204 +0,0 @@
-/*
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/*
- * This file is available under and governed by the GNU General Public
- * License version 2 only, as published by the Free Software Foundation.
- * However, the following notice accompanied the original version of this
- * file:
- *
- * Written by Doug Lea and Martin Buchholz with assistance from
- * members of JCP JSR-166 Expert Group and released to the public
- * domain, as explained at
- * http://creativecommons.org/publicdomain/zero/1.0/
- */
-
-/*
- * @test
- * @bug 8004138 8205576
- * @modules java.base/java.util.concurrent:open
- * @run testng FJExceptionTableLeak
- * @summary Checks that ForkJoinTask thrown exceptions are not leaked.
- * This whitebox test is sensitive to forkjoin implementation details.
- */
-
-import static org.testng.Assert.*;
-import org.testng.annotations.Test;
-
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-
-import java.lang.ref.ReferenceQueue;
-import java.lang.ref.WeakReference;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.VarHandle;
-import java.util.ArrayList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ForkJoinPool;
-import java.util.concurrent.ForkJoinTask;
-import java.util.concurrent.RecursiveAction;
-import java.util.concurrent.ThreadLocalRandom;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.function.BooleanSupplier;
-
-@Test
-public class FJExceptionTableLeak {
-    final ThreadLocalRandom rnd = ThreadLocalRandom.current();
-    final VarHandle NEXT, EX;
-    final Object[] exceptionTable;
-    final ReentrantLock exceptionTableLock;
-
-    FJExceptionTableLeak() throws ReflectiveOperationException {
-        MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(
-            ForkJoinTask.class, MethodHandles.lookup());
-        Class<?> nodeClass = Class.forName(
-            ForkJoinTask.class.getName() + "$ExceptionNode");
-        VarHandle exceptionTableHandle = lookup.findStaticVarHandle(
-            ForkJoinTask.class, "exceptionTable", arrayClass(nodeClass));
-        VarHandle exceptionTableLockHandle = lookup.findStaticVarHandle(
-            ForkJoinTask.class, "exceptionTableLock", ReentrantLock.class);
-        exceptionTable = (Object[]) exceptionTableHandle.get();
-        exceptionTableLock = (ReentrantLock) exceptionTableLockHandle.get();
-
-        NEXT = lookup.findVarHandle(nodeClass, "next", nodeClass);
-        EX = lookup.findVarHandle(nodeClass, "ex", Throwable.class);
-    }
-
-    static <T> Class<T[]> arrayClass(Class<T> klazz) {
-        try {
-            return (Class<T[]>) Class.forName("[L" + klazz.getName() + ";");
-        } catch (ReflectiveOperationException ex) {
-            throw new Error(ex);
-        }
-    }
-
-    Object next(Object node) { return NEXT.get(node); }
-    Throwable ex(Object node) { return (Throwable) EX.get(node); }
-
-    static class FailingTaskException extends RuntimeException {}
-    static class FailingTask extends RecursiveAction {
-        public void compute() { throw new FailingTaskException(); }
-    }
-
-    /** Counts all FailingTaskExceptions still recorded in exceptionTable. */
-    int retainedExceptions() {
-        exceptionTableLock.lock();
-        try {
-            int count = 0;
-            for (Object node : exceptionTable)
-                for (; node != null; node = next(node))
-                    if (ex(node) instanceof FailingTaskException)
-                        count++;
-            return count;
-        } finally {
-            exceptionTableLock.unlock();
-        }
-    }
-
-    @Test
-    public void exceptionTableCleanup() throws Exception {
-        ArrayList<FailingTask> failedTasks = failedTasks();
-
-        // Retain a strong ref to one last failing task
-        FailingTask lastTask = failedTasks.get(rnd.nextInt(failedTasks.size()));
-
-        // Clear all other strong refs, making exception table cleanable
-        failedTasks.clear();
-
-        BooleanSupplier exceptionTableIsClean = () -> {
-            try {
-                // Trigger exception table expunging as side effect
-                lastTask.join();
-                throw new AssertionError("should throw");
-            } catch (FailingTaskException expected) {}
-            int count = retainedExceptions();
-            if (count == 0)
-                throw new AssertionError("expected to find last task");
-            return count == 1;
-        };
-        gcAwait(exceptionTableIsClean);
-    }
-
-    /** Sequestered into a separate method to inhibit GC retention. */
-    ArrayList<FailingTask> failedTasks()
-        throws Exception {
-        final ForkJoinPool pool = new ForkJoinPool(rnd.nextInt(1, 4));
-
-        assertEquals(0, retainedExceptions());
-
-        final ArrayList<FailingTask> tasks = new ArrayList<>();
-
-        for (int i = exceptionTable.length; i--> 0; ) {
-            FailingTask task = new FailingTask();
-            pool.execute(task);
-            tasks.add(task); // retain strong refs to all tasks, for now
-            task = null;     // excessive GC retention paranoia
-        }
-        for (FailingTask task : tasks) {
-            try {
-                task.join();
-                throw new AssertionError("should throw");
-            } catch (FailingTaskException success) {}
-            task = null;     // excessive GC retention paranoia
-        }
-
-        if (rnd.nextBoolean())
-            gcAwait(() -> retainedExceptions() == tasks.size());
-
-        return tasks;
-    }
-
-    // --------------- GC finalization infrastructure ---------------
-
-    /** No guarantees, but effective in practice. */
-    static void forceFullGc() {
-        long timeoutMillis = 1000L;
-        CountDownLatch finalized = new CountDownLatch(1);
-        ReferenceQueue<Object> queue = new ReferenceQueue<>();
-        WeakReference<Object> ref = new WeakReference<>(
-            new Object() { protected void finalize() { finalized.countDown(); }},
-            queue);
-        try {
-            for (int tries = 3; tries--> 0; ) {
-                System.gc();
-                if (finalized.await(timeoutMillis, MILLISECONDS)
-                    && queue.remove(timeoutMillis) != null
-                    && ref.get() == null) {
-                    System.runFinalization(); // try to pick up stragglers
-                    return;
-                }
-                timeoutMillis *= 4;
-            }
-        } catch (InterruptedException unexpected) {
-            throw new AssertionError("unexpected InterruptedException");
-        }
-        throw new AssertionError("failed to do a \"full\" gc");
-    }
-
-    static void gcAwait(BooleanSupplier s) {
-        for (int i = 0; i < 10; i++) {
-            if (s.getAsBoolean())
-                return;
-            forceFullGc();
-        }
-        throw new AssertionError("failed to satisfy condition");
-    }
-}

test/jdk/java/util/concurrent/tck/ForkJoinTaskTest.java

@@ -1720,4 +1720,20 @@ public class ForkJoinTaskTest extends JSR166TestCase {
                 task.toString());
         }
     }
+
+    // adaptInterruptible deferred to its own independent change
+    // https://bugs.openjdk.java.net/browse/JDK-8246587
+
+//     /**
+//      * adaptInterruptible(callable).toString() contains toString of wrapped task
+//      */
+//     public void testAdaptInterruptible_Callable_toString() {
+//         if (testImplementationDetails) {
+//             Callable<String> c = () -> "";
+//             ForkJoinTask<String> task = ForkJoinTask.adaptInterruptible(c);
+//             assertEquals(
+//                 identityString(task) + "[Wrapped task = " + c.toString() + "]",
+//                 task.toString());
+//         }
+//     }
 }