--- jsr166/src/test/tck/JSR166TestCase.java	2015/09/28 08:23:49	1.148
+++ jsr166/src/test/tck/JSR166TestCase.java	2015/10/03 21:09:42	1.156
@@ -7,6 +7,7 @@
  */
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 
 import java.io.ByteArrayInputStream;
@@ -15,6 +16,7 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
@@ -186,7 +188,27 @@ public class JSR166TestCase extends Test
         return (regex == null) ? null : Pattern.compile(regex);
     }
 
+    static volatile TestCase currentTestCase;
+    static {
+        Runnable checkForWedgedTest = new Runnable() { public void run() {
+            for (TestCase lastTestCase = currentTestCase;;) {
+                try { MINUTES.sleep(10); }
+                catch (InterruptedException unexpected) { break; }
+                if (lastTestCase == currentTestCase) {
+                    System.err.println
+                        ("Looks like we're stuck running test: "
+                         + lastTestCase);
+                    dumpTestThreads();
+                }
+                lastTestCase = currentTestCase;
+            }}};
+        Thread thread = new Thread(checkForWedgedTest, "checkForWedgedTest");
+        thread.setDaemon(true);
+        thread.start();
+    }
+
     public void runBare() throws Throwable {
+        currentTestCase = this;
         if (methodFilter == null
             || methodFilter.matcher(toString()).find())
             super.runBare();
@@ -460,7 +482,6 @@ public class JSR166TestCase extends Test
         } else {
             return new TestSuite();
         }
-
     }
 
     // Delays for timing-dependent tests, in milliseconds.
@@ -518,6 +539,7 @@ public class JSR166TestCase extends Test
      * the same test have no effect.
      */
     public void threadRecordFailure(Throwable t) {
+        dumpTestThreads();
         threadFailure.compareAndSet(null, t);
     }
 
@@ -528,7 +550,7 @@ public class JSR166TestCase extends Test
     void tearDownFail(String format, Object... args) {
         String msg = toString() + ": " + String.format(format, args);
         System.err.println(msg);
-        printAllStackTraces();
+        dumpTestThreads();
         throw new AssertionFailedError(msg);
     }
 
@@ -597,7 +619,7 @@ public class JSR166TestCase extends Test
             fail(reason);
         } catch (AssertionFailedError t) {
             threadRecordFailure(t);
-            fail(reason);
+            throw t;
         }
     }
 
@@ -743,9 +765,19 @@ public class JSR166TestCase extends Test
     }
 
     /**
+     * Allows use of try-with-resources with per-test thread pools.
+     */
+    static class PoolCloser<T extends ExecutorService>
+            implements AutoCloseable {
+        public final T pool;
+        public PoolCloser(T pool) { this.pool = pool; }
+        public void close() { joinPool(pool); }
+    }
+
+    /**
      * Waits out termination of a thread pool or fails doing so.
      */
-    void joinPool(ExecutorService pool) {
+    static void joinPool(ExecutorService pool) {
         try {
             pool.shutdown();
             if (!pool.awaitTermination(2 * LONG_DELAY_MS, MILLISECONDS))
@@ -767,8 +799,9 @@ public class JSR166TestCase extends Test
      * necessarily individually slow because they must block.
      */
     void testInParallel(Action ... actions) {
-        ExecutorService pool = Executors.newCachedThreadPool();
-        try {
+        try (PoolCloser<ExecutorService> poolCloser
+             = new PoolCloser<>(Executors.newCachedThreadPool())) {
+            ExecutorService pool = poolCloser.pool;
             ArrayList<Future<?>> futures = new ArrayList<>(actions.length);
             for (final Action action : actions)
                 futures.add(pool.submit(new CheckedRunnable() {
@@ -781,19 +814,31 @@ public class JSR166TestCase extends Test
                 } catch (Exception ex) {
                     threadUnexpectedException(ex);
                 }
-        } finally {
-            joinPool(pool);
         }
     }
 
     /**
-     * A debugging tool to print all stack traces, as jstack does.
+     * A debugging tool to print stack traces of most threads, as jstack does.
+     * Uninteresting threads are filtered out.
      */
-    static void printAllStackTraces() {
-        for (ThreadInfo info :
-                 ManagementFactory.getThreadMXBean()
-                 .dumpAllThreads(true, true))
+    static void dumpTestThreads() {
+        ThreadMXBean threadMXBean = ManagementFactory.getThreadMXBean();
+        System.err.println("------ stacktrace dump start ------");
+        for (ThreadInfo info : threadMXBean.dumpAllThreads(true, true)) {
+            String name = info.getThreadName();
+            if ("Signal Dispatcher".equals(name))
+                continue;
+            if ("Reference Handler".equals(name)
+                && info.getLockName().startsWith("java.lang.ref.Reference$Lock"))
+                continue;
+            if ("Finalizer".equals(name)
+                && info.getLockName().startsWith("java.lang.ref.ReferenceQueue$Lock"))
+                continue;
+            if ("checkForWedgedTest".equals(name))
+                continue;
             System.err.print(info);
+        }
+        System.err.println("------ stacktrace dump end ------");
     }
 
     /**