--- old/test/java/util/concurrent/ThreadPoolExecutor/ThrowingTasks.java	2013-11-04 11:49:44.425183554 +0800
+++ new/test/java/util/concurrent/ThreadPoolExecutor/ThrowingTasks.java	2013-11-04 11:49:43.857183529 +0800
@@ -33,6 +33,7 @@
 import java.util.*;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.*;
+import java.util.concurrent.locks.ReentrantLock;
 
 public class ThrowingTasks {
     static final Random rnd = new Random();
@@ -156,6 +157,7 @@
     }
 
     static class CheckingExecutor extends ThreadPoolExecutor {
+        private final ReentrantLock lock = new ReentrantLock();
         CheckingExecutor() {
             super(10, 10,
                   1L, TimeUnit.HOURS,
@@ -163,8 +165,17 @@
                   tf);
         }
         @Override protected void beforeExecute(Thread t, Runnable r) {
-            allStarted.countDown();
-            if (allStarted.getCount() < getCorePoolSize())
+            final boolean lessThanCorePoolSize;
+            // Add a lock to sync allStarted.countDown() and 
+            // allStarted.getCount() < getCorePoolSize()
+            lock.lock();
+            try {
+                allStarted.countDown();
+                lessThanCorePoolSize = allStarted.getCount() < getCorePoolSize();
+            } finally {
+                lock.unlock();
+            }
+            if (lessThanCorePoolSize)
                 try { allContinue.await(); }
                 catch (InterruptedException x) { unexpected(x); }
             beforeExecuteCount.getAndIncrement();