diff --git a/runners/google-cloud-dataflow-java/worker/src/test/java/org/apache/beam/runners/dataflow/worker/StreamingDataflowWorkerTest.java b/runners/google-cloud-dataflow-java/worker/src/test/java/org/apache/beam/runners/dataflow/worker/StreamingDataflowWorkerTest.java
index 357b884fbb18..b7f4c850bbb7 100644
--- a/runners/google-cloud-dataflow-java/worker/src/test/java/org/apache/beam/runners/dataflow/worker/StreamingDataflowWorkerTest.java
+++ b/runners/google-cloud-dataflow-java/worker/src/test/java/org/apache/beam/runners/dataflow/worker/StreamingDataflowWorkerTest.java
@@ -2764,6 +2764,7 @@ public void run() {}
   }
 
   private static class MockActiveWork extends StreamingDataflowWorker.Work {
+    // exit must be volatile so changes to it are reflected in the run function
     public static volatile boolean exit;
 
     public MockActiveWork(long workToken) {
@@ -2945,13 +2946,13 @@ public void run() {
   @Test
   public void testActiveThreadMetric() throws Exception {
     int maxThreads = 5;
-    int threadExpiration = 60;
+    int threadExpirationSec = 60;
     // setting up actual implementation of executor instead of mocking to keep track of
     // active thread count.
     BoundedQueueExecutor executor =
         new BoundedQueueExecutor(
             maxThreads,
-            threadExpiration,
+            threadExpirationSec,
             TimeUnit.SECONDS,
             maxThreads,
             10000000,
@@ -2975,6 +2976,9 @@ public void testActiveThreadMetric() throws Exception {
         new MockActiveWork(1) {
           @Override
           public void run() {
+            synchronized(this) {
+              this.notify();
+            }
             int count = 0;
             while (!exit) {
               count += 1;
@@ -2988,6 +2992,9 @@ public void run() {
         new MockWork(2) {
           @Override
           public void run() {
+            synchronized(this) {
+              this.notify();
+            }
             try {
               Thread.sleep(2000);
             } catch (InterruptedException e) {
@@ -3001,6 +3008,9 @@ public void run() {
         new MockWork(3) {
           @Override
           public void run() {
+            synchronized(this) {
+              this.notify();
+            }
             try {
               Thread.sleep(2000);
             } catch (InterruptedException e) {
@@ -3011,15 +3021,25 @@ public void run() {
     assertEquals(0, executor.activeCount());
 
     assertTrue(computationState.activateWork(key1Shard1, m1));
-    executor.execute(m1, m1.getWorkItem().getSerializedSize());
-    Thread.sleep(1000);
+    synchronized (m1) {
+      executor.execute(m1, m1.getWorkItem().getSerializedSize());
+      LOG.info("[chengedward] waiting on thread start m1]");
+      m1.wait();
+    }
+    LOG.info("[chengedward] thread started m1]");
     assertEquals(2, executor.activeCount());
-
+    
     assertTrue(computationState.activateWork(key1Shard1, m2));
     assertTrue(computationState.activateWork(key1Shard1, m3));
-    executor.execute(m2, m2.getWorkItem().getSerializedSize());
-    executor.execute(m3, m3.getWorkItem().getSerializedSize());
-    Thread.sleep(1000);
+    synchronized (m2) {
+      executor.execute(m2, m2.getWorkItem().getSerializedSize());
+      m2.wait();
+    }
+    synchronized (m3) {
+      executor.execute(m3, m3.getWorkItem().getSerializedSize());
+      m3.wait();
+    }
+    // this.wait();
     assertEquals(4, executor.activeCount());
 
     m1.stop();