test/jdk/java/util/concurrent/ArrayBlockingQueue/WhiteBox.java
changeset 50229 6b29ef846c5c
parent 48843 21efc1774302
child 50764 5637aca18f1d
--- a/test/jdk/java/util/concurrent/ArrayBlockingQueue/WhiteBox.java	Tue May 22 21:46:51 2018 -0700
+++ b/test/jdk/java/util/concurrent/ArrayBlockingQueue/WhiteBox.java	Tue May 22 21:50:45 2018 -0700
@@ -38,10 +38,12 @@
  * @summary White box tests of implementation details
  */
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.testng.Assert.*;
 
 import org.testng.annotations.Test;
 
+import java.lang.ref.ReferenceQueue;
 import java.lang.ref.WeakReference;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
@@ -202,16 +204,22 @@
 
     /** No guarantees, but effective in practice. */
     static void forceFullGc() {
-        CountDownLatch finalizeDone = new CountDownLatch(1);
-        WeakReference<?> ref = new WeakReference<Object>(new Object() {
-            protected void finalize() { finalizeDone.countDown(); }});
+        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 i = 0; i < 10; i++) {
+            for (int tries = 3; tries--> 0; ) {
                 System.gc();
-                if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
+                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");