diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt
index 75c819b..ac3d713 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt
@@ -156,6 +156,7 @@
     @After
     fun tearDown() {
         fakeTetheringThread.quitSafely()
+        fakeTetheringThread.join()
     }
 
     private fun verifyActivityPendingIntent(intent: Intent, flags: Int) {
diff --git a/tests/common/java/android/net/NetworkProviderTest.kt b/tests/common/java/android/net/NetworkProviderTest.kt
index c0e7f61..fcbb0dd 100644
--- a/tests/common/java/android/net/NetworkProviderTest.kt
+++ b/tests/common/java/android/net/NetworkProviderTest.kt
@@ -79,6 +79,7 @@
     @After
     fun tearDown() {
         mHandlerThread.quitSafely()
+        mHandlerThread.join()
         instrumentation.getUiAutomation().dropShellPermissionIdentity()
     }
 
diff --git a/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt b/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
index f578ff3..b535a8f 100644
--- a/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
@@ -191,6 +191,7 @@
         callbacksToCleanUp.forEach { mCM.unregisterNetworkCallback(it) }
         qosTestSocket?.close()
         mHandlerThread.quitSafely()
+        mHandlerThread.join()
         instrumentation.getUiAutomation().dropShellPermissionIdentity()
     }
 
diff --git a/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt b/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
index eb41d71..fcfecad 100644
--- a/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
@@ -90,6 +90,7 @@
         mCm.unregisterNetworkCallback(agentCleanUpCb)
 
         mHandlerThread.quitSafely()
+        mHandlerThread.join()
         callbacksToCleanUp.forEach { mCm.unregisterNetworkCallback(it) }
     }
 
diff --git a/tests/cts/net/src/android/net/cts/NetworkValidationTest.kt b/tests/cts/net/src/android/net/cts/NetworkValidationTest.kt
index 8e98dba..621af23 100644
--- a/tests/cts/net/src/android/net/cts/NetworkValidationTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkValidationTest.kt
@@ -146,6 +146,7 @@
         httpServer.stop()
         handlerThread.threadHandler.post { reader.stop() }
         handlerThread.quitSafely()
+        handlerThread.join()
 
         iface.fileDescriptor.close()
     }
diff --git a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
index 6fd2321..db4f937 100644
--- a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
@@ -432,6 +432,7 @@
         }
         handlerThread.waitForIdle(TIMEOUT_MS)
         handlerThread.quitSafely()
+        handlerThread.join()
     }
 
     @Test
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index c1c6a8a..6c89c38 100755
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -2219,7 +2219,9 @@
         ConnectivityResources.setResourcesContextForTest(null);
 
         mCsHandlerThread.quitSafely();
+        mCsHandlerThread.join();
         mAlarmManagerThread.quitSafely();
+        mAlarmManagerThread.join();
     }
 
     private void mockDefaultPackages() throws Exception {
@@ -10126,6 +10128,7 @@
         b2.expectBroadcast();
 
         VMSHandlerThread.quitSafely();
+        VMSHandlerThread.join();
     }
 
     @Test @IgnoreUpTo(Build.VERSION_CODES.S_V2)
@@ -16974,6 +16977,7 @@
         } finally {
             cellFactory.terminate();
             handlerThread.quitSafely();
+            handlerThread.join();
         }
     }
 
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
index 375c150..a917361 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAdvertiserTest.kt
@@ -97,6 +97,7 @@
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     @Test
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAnnouncerTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAnnouncerTest.kt
index 6c3f729..7c6cb3e 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsAnnouncerTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsAnnouncerTest.kt
@@ -63,6 +63,7 @@
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     private class TestAnnouncementInfo(
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsInterfaceAdvertiserTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsInterfaceAdvertiserTest.kt
index 2d8d8f3..0ca0835 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsInterfaceAdvertiserTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsInterfaceAdvertiserTest.kt
@@ -136,6 +136,7 @@
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     @Test
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsProberTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsProberTest.kt
index a2dbbc6..2b5423b 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsProberTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsProberTest.kt
@@ -68,6 +68,7 @@
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     private class TestProbeInfo(probeRecords: List<MdnsRecord>, private val delayMs: Long = 1L) :
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
index 5665091..44e0d08 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsRecordRepositoryTest.kt
@@ -79,6 +79,7 @@
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     @Test
diff --git a/tests/unit/java/com/android/server/ethernet/EthernetTrackerTest.java b/tests/unit/java/com/android/server/ethernet/EthernetTrackerTest.java
index 5e7f0ff..e6aba22 100644
--- a/tests/unit/java/com/android/server/ethernet/EthernetTrackerTest.java
+++ b/tests/unit/java/com/android/server/ethernet/EthernetTrackerTest.java
@@ -86,8 +86,9 @@
     }
 
     @After
-    public void cleanUp() {
+    public void cleanUp() throws InterruptedException {
         mHandlerThread.quitSafely();
+        mHandlerThread.join();
     }
 
     private void initMockResources() {
diff --git a/tests/unit/java/com/android/server/net/IpConfigStoreTest.java b/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
index 19ded24..dcf0f75 100644
--- a/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
+++ b/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
@@ -36,7 +36,6 @@
 
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
-import com.android.testutils.HandlerUtils;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -139,6 +138,8 @@
                     }
                     @Override
                     public void quitHandlerThread(HandlerThread handlerThread) {
+                        // Don't join in here, quitHandlerThread runs on the
+                        // handler thread itself.
                         testHandlerThread.quitSafely();
                     }
         };
@@ -155,7 +156,7 @@
         final DelayedDiskWrite writer = new DelayedDiskWrite(dependencies);
         final IpConfigStore store = new IpConfigStore(writer);
         store.writeIpConfigurations(configFile.getPath(), expectedNetworks);
-        HandlerUtils.waitForIdle(testHandlerThread, TIMEOUT_MS);
+        testHandlerThread.join();
 
         // Read IP config from the file path.
         final ArrayMap<String, IpConfiguration> actualNetworks =
diff --git a/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java b/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
index 8046263..04163fd 100644
--- a/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
+++ b/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
@@ -539,6 +539,7 @@
         mService = null;
 
         mHandlerThread.quitSafely();
+        mHandlerThread.join();
     }
 
     private void initWifiStats(NetworkStateSnapshot snapshot) throws Exception {