diff --git a/framework/api/module-lib-current.txt b/framework/api/module-lib-current.txt
index 4719772..9e2cd3e 100644
--- a/framework/api/module-lib-current.txt
+++ b/framework/api/module-lib-current.txt
@@ -13,7 +13,7 @@
     method @NonNull public static String getPrivateDnsMode(@NonNull android.content.Context);
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerDefaultNetworkCallbackAsUid(int, @NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @RequiresPermission(anyOf={android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK, android.Manifest.permission.NETWORK_SETTINGS}) public void registerSystemDefaultNetworkCallback(@NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
-    method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void requestBackgroundNetwork(@NonNull android.net.NetworkRequest, @NonNull android.os.Handler, @NonNull android.net.ConnectivityManager.NetworkCallback);
+    method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void requestBackgroundNetwork(@NonNull android.net.NetworkRequest, @NonNull android.net.ConnectivityManager.NetworkCallback, @NonNull android.os.Handler);
     method @Deprecated public boolean requestRouteToHostAddress(int, java.net.InetAddress);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_SETUP_WIZARD, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void setAcceptPartialConnectivity(@NonNull android.net.Network, boolean, boolean);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_SETUP_WIZARD, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void setAcceptUnvalidated(@NonNull android.net.Network, boolean, boolean);
diff --git a/framework/src/android/net/ConnectivityFrameworkInitializer.java b/framework/src/android/net/ConnectivityFrameworkInitializer.java
index 92a792b..a2e218d 100644
--- a/framework/src/android/net/ConnectivityFrameworkInitializer.java
+++ b/framework/src/android/net/ConnectivityFrameworkInitializer.java
@@ -68,5 +68,11 @@
                     return cm.startOrGetTestNetworkManager();
                 }
         );
+
+        SystemServiceRegistry.registerContextAwareService(
+                DnsResolverServiceManager.DNS_RESOLVER_SERVICE,
+                DnsResolverServiceManager.class,
+                (context, serviceBinder) -> new DnsResolverServiceManager(serviceBinder)
+        );
     }
 }
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 0418450..043ff38 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -5307,10 +5307,10 @@
      * {@link #unregisterNetworkCallback(NetworkCallback)}.
      *
      * @param request {@link NetworkRequest} describing this request.
-     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
-     *                If null, the callback is invoked on the default internal Handler.
      * @param networkCallback The {@link NetworkCallback} to be utilized for this request. Note
      *                        the callback must not be shared - it uniquely specifies this request.
+     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     *                If null, the callback is invoked on the default internal Handler.
      * @throws IllegalArgumentException if {@code request} contains invalid network capabilities.
      * @throws SecurityException if missing the appropriate permissions.
      * @throws RuntimeException if the app already has too many callbacks registered.
@@ -5325,7 +5325,8 @@
             NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK
     })
     public void requestBackgroundNetwork(@NonNull NetworkRequest request,
-            @NonNull Handler handler, @NonNull NetworkCallback networkCallback) {
+            @NonNull NetworkCallback networkCallback,
+            @SuppressLint("ListenerLast") @NonNull Handler handler) {
         final NetworkCapabilities nc = request.networkCapabilities;
         sendRequestForNetwork(nc, networkCallback, 0, BACKGROUND_REQUEST,
                 TYPE_NONE, new CallbackHandler(handler));
diff --git a/framework/src/android/net/DnsResolverServiceManager.java b/framework/src/android/net/DnsResolverServiceManager.java
new file mode 100644
index 0000000..79009e8
--- /dev/null
+++ b/framework/src/android/net/DnsResolverServiceManager.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net;
+
+import android.annotation.NonNull;
+import android.os.IBinder;
+
+/**
+ * Provides a way to obtain the DnsResolver binder objects.
+ *
+ * @hide
+ */
+public class DnsResolverServiceManager {
+    /** Service name for the DNS resolver. Keep in sync with DnsResolverService.h */
+    public static final String DNS_RESOLVER_SERVICE = "dnsresolver";
+
+    private final IBinder mResolver;
+
+    DnsResolverServiceManager(IBinder resolver) {
+        mResolver = resolver;
+    }
+
+    /**
+     * Get an {@link IBinder} representing the DnsResolver stable AIDL interface
+     *
+     * @return {@link android.net.IDnsResolver} IBinder.
+     */
+    @NonNull
+    public IBinder getService() {
+        return mResolver;
+    }
+}
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index a1e3d32..2216e89 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -616,7 +616,9 @@
     }
 
     private static IDnsResolver getDnsResolver(Context context) {
-        return IDnsResolver.Stub.asInterface(DnsResolverServiceManager.getService(context));
+        final DnsResolverServiceManager dsm = context.getSystemService(
+                DnsResolverServiceManager.class);
+        return IDnsResolver.Stub.asInterface(dsm.getService());
     }
 
     /** Handler thread used for all of the handlers below. */
@@ -6143,6 +6145,7 @@
     @Override
     public int registerNetworkProvider(Messenger messenger, String name) {
         enforceNetworkFactoryOrSettingsPermission();
+        Objects.requireNonNull(messenger, "messenger must be non-null");
         NetworkProviderInfo npi = new NetworkProviderInfo(name, messenger,
                 nextNetworkProviderId(), () -> unregisterNetworkProvider(messenger));
         mHandler.sendMessage(mHandler.obtainMessage(EVENT_REGISTER_NETWORK_PROVIDER, npi));
@@ -9075,6 +9078,7 @@
     @Override
     public void unregisterConnectivityDiagnosticsCallback(
             @NonNull IConnectivityDiagnosticsCallback callback) {
+        Objects.requireNonNull(callback, "callback must be non-null");
         mConnectivityDiagnosticsHandler.sendMessage(
                 mConnectivityDiagnosticsHandler.obtainMessage(
                         ConnectivityDiagnosticsHandler
@@ -9445,6 +9449,7 @@
      */
     @Override
     public void unregisterQosCallback(@NonNull final IQosCallback callback) {
+        Objects.requireNonNull(callback, "callback must be non-null");
         mQosCallbackTracker.unregisterCallback(callback);
     }
 
diff --git a/tests/net/common/java/ParseExceptionTest.kt b/tests/net/common/java/ParseExceptionTest.kt
new file mode 100644
index 0000000..f17715a
--- /dev/null
+++ b/tests/net/common/java/ParseExceptionTest.kt
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import android.net.ParseException
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.SmallTest
+import junit.framework.Assert.assertEquals
+import junit.framework.Assert.assertNull
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@SmallTest
+@RunWith(AndroidJUnit4::class)
+class ParseExceptionTest {
+    @Test
+    fun testConstructor_WithCause() {
+        val testMessage = "Test message"
+        val base = Exception("Test")
+        val exception = ParseException(testMessage, base)
+
+        assertEquals(testMessage, exception.response)
+        assertEquals(base, exception.cause)
+    }
+
+    @Test
+    fun testConstructor_NoCause() {
+        val testMessage = "Test message"
+        val exception = ParseException(testMessage)
+
+        assertEquals(testMessage, exception.response)
+        assertNull(exception.cause)
+    }
+}
\ No newline at end of file
diff --git a/tests/net/java/android/net/ConnectivityManagerTest.java b/tests/net/java/android/net/ConnectivityManagerTest.java
index 6cbdd25..19f8843 100644
--- a/tests/net/java/android/net/ConnectivityManagerTest.java
+++ b/tests/net/java/android/net/ConnectivityManagerTest.java
@@ -384,7 +384,7 @@
                 eq(TRACK_DEFAULT.ordinal()), any(), anyInt(), any(), eq(TYPE_NONE), anyInt(),
                 eq(testPkgName), eq(testAttributionTag));
 
-        manager.requestBackgroundNetwork(request, handler, callback);
+        manager.requestBackgroundNetwork(request, callback, handler);
         verify(mService).requestNetwork(eq(Process.INVALID_UID), eq(request.networkCapabilities),
                 eq(BACKGROUND_REQUEST.ordinal()), any(), anyInt(), any(), eq(TYPE_NONE), anyInt(),
                 eq(testPkgName), eq(testAttributionTag));
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 790f3be..91811f6 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -4262,7 +4262,7 @@
         final TestNetworkCallback cellBgCallback = new TestNetworkCallback();
         mCm.requestBackgroundNetwork(new NetworkRequest.Builder()
                 .addTransportType(TRANSPORT_CELLULAR).build(),
-                mCsHandlerThread.getThreadHandler(), cellBgCallback);
+                cellBgCallback, mCsHandlerThread.getThreadHandler());
 
         // Make callbacks for monitoring.
         final NetworkRequest request = new NetworkRequest.Builder().build();