[Backport 2.x] Workaround for https://bugs.openjdk.org/browse/JDK-8323659 regression, introduced in JDK-21.0.2

CHANGELOG.md

@@ -118,6 +118,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Use slice_size == shard_size heuristic in terms aggs for concurrent segment search and properly calculate the doc_count_error ([#11732](https://github.com/opensearch-project/OpenSearch/pull/11732))
 - Ensure Jackson default maximums introduced in 2.16.0 do not conflict with OpenSearch settings ([#11890](https://github.com/opensearch-project/OpenSearch/pull/11890))
 - Extract cluster management for integration tests into JUnit test rule out of OpenSearchIntegTestCase ([#11877](https://github.com/opensearch-project/OpenSearch/pull/11877))
+- Workaround for https://bugs.openjdk.org/browse/JDK-8323659 regression, introduced in JDK-21.0.2 ([#11968](https://github.com/opensearch-project/OpenSearch/pull/11968))
 
 ### Deprecated
 

server/src/main/java/org/opensearch/common/util/concurrent/OpenSearchExecutors.java

@@ -449,6 +449,30 @@
             }
         }
 
+        /**
+         * Workaround for https://bugs.openjdk.org/browse/JDK-8323659 regression, introduced in JDK-21.0.2.
+         */
+        @Override
+        public void put(E e) {
+            super.offer(e);
+        }
+
+        /**
+         * Workaround for https://bugs.openjdk.org/browse/JDK-8323659 regression, introduced in JDK-21.0.2.
+         */
+        @Override
+        public boolean offer(E e, long timeout, TimeUnit unit) {
+            return super.offer(e);
+        }
+
+        /**
+         * Workaround for https://bugs.openjdk.org/browse/JDK-8323659 regression, introduced in JDK-21.0.2.
+         */
+        @Override
+        public boolean add(E e) {
+            return super.offer(e);
+        }
+
     }
 
     /**

server/src/test/java/org/opensearch/common/util/concurrent/OpenSearchExecutorsTests.java

@@ -49,6 +49,7 @@
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.lessThan;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 /**
  * Tests for OpenSearchExecutors and its components like OpenSearchAbortPolicy.
@@ -279,6 +280,41 @@ public void testScaleDown() throws Exception {
         terminate(pool);
     }
 
+    /**
+     * The test case is adapted from https://bugs.openjdk.org/browse/JDK-8323659 reproducer.
+     */
+    public void testScaleUpWithSpawningTask() throws Exception {
+        ThreadPoolExecutor pool = OpenSearchExecutors.newScaling(
+            getClass().getName() + "/" + getTestName(),
+            0,
+            1,
+            between(1, 100),
+            randomTimeUnit(),
+            OpenSearchExecutors.daemonThreadFactory("test"),
+            threadContext
+        );
+        assertThat("Min property", pool.getCorePoolSize(), equalTo(0));
+        assertThat("Max property", pool.getMaximumPoolSize(), equalTo(1));
+
+        final CountDownLatch latch = new CountDownLatch(10);
+        class TestTask implements Runnable {
+            @Override
+            public void run() {
+                latch.countDown();
+                if (latch.getCount() > 0) {
+                    pool.execute(TestTask.this);
+                }
+            }
+        }
+        pool.execute(new TestTask());
+        latch.await();
+
+        assertThat("wrong pool size", pool.getPoolSize(), lessThanOrEqualTo(1));
+        assertThat("wrong active size", pool.getActiveCount(), lessThanOrEqualTo(1));
+
+        terminate(pool);
+    }
+
     public void testRejectionMessageAndShuttingDownFlag() throws InterruptedException {
         int pool = between(1, 10);
         int queue = between(0, 100);