diff --git a/service-t/src/com/android/server/net/NetworkStatsObservers.java b/service-t/src/com/android/server/net/NetworkStatsObservers.java
index 9aa20a4..b57a4f9 100644
--- a/service-t/src/com/android/server/net/NetworkStatsObservers.java
+++ b/service-t/src/com/android/server/net/NetworkStatsObservers.java
@@ -18,8 +18,6 @@
 
 import static android.app.usage.NetworkStatsManager.MIN_THRESHOLD_BYTES;
 
-import static com.android.internal.util.Preconditions.checkArgument;
-
 import android.app.usage.NetworkStatsManager;
 import android.net.DataUsageRequest;
 import android.net.NetworkIdentitySet;
@@ -216,7 +214,10 @@
                     accessLevel);
         } else {
             // Safety check in case a new access level is added and we forgot to update this
-            checkArgument(accessLevel >= NetworkStatsAccess.Level.DEVICESUMMARY);
+            if (accessLevel < NetworkStatsAccess.Level.DEVICESUMMARY) {
+                throw new IllegalArgumentException(
+                        "accessLevel " + accessLevel + " is less than DEVICESUMMARY.");
+            }
             return new NetworkUsageRequestInfo(this, request, messenger, binder, callingUid,
                     accessLevel);
         }
diff --git a/service-t/src/com/android/server/net/NetworkStatsRecorder.java b/service-t/src/com/android/server/net/NetworkStatsRecorder.java
index cec6609..c371f08 100644
--- a/service-t/src/com/android/server/net/NetworkStatsRecorder.java
+++ b/service-t/src/com/android/server/net/NetworkStatsRecorder.java
@@ -34,12 +34,10 @@
 import android.service.NetworkStatsRecorderProto;
 import android.util.IndentingPrintWriter;
 import android.util.Log;
-import android.util.MathUtils;
 import android.util.proto.ProtoOutputStream;
 
 import com.android.internal.util.FileRotator;
-
-import com.google.android.collect.Sets;
+import com.android.net.module.util.NetworkStatsUtils;
 
 import libcore.io.IoUtils;
 
@@ -132,7 +130,7 @@
 
     public void setPersistThreshold(long thresholdBytes) {
         if (LOGV) Log.v(TAG, "setPersistThreshold() with " + thresholdBytes);
-        mPersistThresholdBytes = MathUtils.constrain(
+        mPersistThresholdBytes = NetworkStatsUtils.constrain(
                 thresholdBytes, 1 * KB_IN_BYTES, 100 * MB_IN_BYTES);
     }
 
@@ -206,7 +204,7 @@
      */
     public void recordSnapshotLocked(NetworkStats snapshot,
             Map<String, NetworkIdentitySet> ifaceIdent, long currentTimeMillis) {
-        final HashSet<String> unknownIfaces = Sets.newHashSet();
+        final HashSet<String> unknownIfaces = new HashSet<>();
 
         // skip recording when snapshot missing
         if (snapshot == null) return;
diff --git a/service-t/src/com/android/server/net/NetworkStatsService.java b/service-t/src/com/android/server/net/NetworkStatsService.java
index 44d7d1f..4fd62c1 100644
--- a/service-t/src/com/android/server/net/NetworkStatsService.java
+++ b/service-t/src/com/android/server/net/NetworkStatsService.java
@@ -25,7 +25,6 @@
 import static android.content.Intent.EXTRA_UID;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.net.NetworkIdentity.SUBTYPE_COMBINED;
-import static android.net.NetworkStack.checkNetworkStackPermission;
 import static android.net.NetworkStats.DEFAULT_NETWORK_ALL;
 import static android.net.NetworkStats.IFACE_ALL;
 import static android.net.NetworkStats.IFACE_VT;
@@ -158,6 +157,7 @@
 
 import java.io.File;
 import java.io.FileDescriptor;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.time.Clock;
@@ -985,7 +985,7 @@
             @NonNull NetworkStateSnapshot[] networkStates,
             @Nullable String activeIface,
             @NonNull UnderlyingNetworkInfo[] underlyingNetworkInfos) {
-        checkNetworkStackPermission(mContext);
+        PermissionUtils.enforceNetworkStackPermission(mContext);
 
         final long token = Binder.clearCallingIdentity();
         try {
@@ -1201,13 +1201,13 @@
             // On background handler thread, and USER_REMOVED is protected
             // broadcast.
 
-            final int userId = intent.getIntExtra(Intent.EXTRA_USER_HANDLE, -1);
-            if (userId == -1) return;
+            final UserHandle userHandle = intent.getParcelableExtra(Intent.EXTRA_USER);
+            if (userHandle == null) return;
 
             synchronized (mStatsLock) {
                 mWakeLock.acquire();
                 try {
-                    removeUserLocked(userId);
+                    removeUserLocked(userHandle);
                 } finally {
                     mWakeLock.release();
                 }
@@ -1232,7 +1232,7 @@
         @Override
         public void limitReached(String limitName, String iface) {
             // only someone like NMS should be calling us
-            NetworkStack.checkNetworkStackPermission(mContext);
+            PermissionUtils.enforceNetworkStackPermission(mContext);
 
             if (LIMIT_GLOBAL_ALERT.equals(limitName)) {
                 // kick off background poll to collect network stats unless there is already
@@ -1652,8 +1652,8 @@
      * Clean up {@link #mUidRecorder} after user is removed.
      */
     @GuardedBy("mStatsLock")
-    private void removeUserLocked(int userId) {
-        if (LOGV) Log.v(TAG, "removeUserLocked() for userId=" + userId);
+    private void removeUserLocked(@NonNull UserHandle userHandle) {
+        if (LOGV) Log.v(TAG, "removeUserLocked() for UserHandle=" + userHandle);
 
         // Build list of UIDs that we should clean up
         final ArrayList<Integer> uids = new ArrayList<>();
@@ -1661,7 +1661,7 @@
                 PackageManager.MATCH_ANY_USER
                 | PackageManager.MATCH_DISABLED_COMPONENTS);
         for (ApplicationInfo app : apps) {
-            final int uid = UserHandle.getUid(userId, app.uid);
+            final int uid = userHandle.getUid(app.uid);
             uids.add(uid);
         }
 
@@ -1869,7 +1869,7 @@
 
     @GuardedBy("mStatsLock")
     private void dumpProtoLocked(FileDescriptor fd) {
-        final ProtoOutputStream proto = new ProtoOutputStream(fd);
+        final ProtoOutputStream proto = new ProtoOutputStream(new FileOutputStream(fd));
 
         // TODO Right now it writes all history.  Should it limit to the "since-boot" log?
 
diff --git a/service-t/src/com/android/server/net/NetworkStatsSubscriptionsMonitor.java b/service-t/src/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
index 5646c75..93d0ae7 100644
--- a/service-t/src/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
+++ b/service-t/src/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
@@ -33,7 +33,7 @@
 import android.util.Pair;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.CollectionUtils;
+import com.android.net.module.util.CollectionUtils;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -99,18 +99,19 @@
         // prevent binder call to telephony when querying RAT. Keep listener registration with empty
         // IMSI is meaningless since the RAT type changed is ambiguous for multi-SIM if reported
         // with empty IMSI. So filter the subs w/o a valid IMSI to prevent such registration.
-        final List<Pair<Integer, String>> filteredNewSubs =
-                CollectionUtils.mapNotNull(newSubs, subId -> {
-                    final String subscriberId = mTeleManager.getSubscriberId(subId);
-                    return TextUtils.isEmpty(subscriberId) ? null : new Pair(subId, subscriberId);
-                });
+        final List<Pair<Integer, String>> filteredNewSubs = new ArrayList<>();
+        for (final int subId : newSubs) {
+            final String subscriberId = mTeleManager.getSubscriberId(subId);
+            if (!TextUtils.isEmpty(subscriberId)) {
+                filteredNewSubs.add(new Pair(subId, subscriberId));
+            }
+        }
 
         for (final Pair<Integer, String> sub : filteredNewSubs) {
             // Fully match listener with subId and IMSI, since in some rare cases, IMSI might be
             // suddenly change regardless of subId, such as switch IMSI feature in modem side.
             // If that happens, register new listener with new IMSI and remove old one later.
-            if (CollectionUtils.find(mRatListeners,
-                    it -> it.equalsKey(sub.first, sub.second)) != null) {
+            if (CollectionUtils.any(mRatListeners, it -> it.equalsKey(sub.first, sub.second))) {
                 continue;
             }
 
@@ -126,8 +127,8 @@
 
         for (final RatTypeListener listener : new ArrayList<>(mRatListeners)) {
             // If there is no subId and IMSI matched the listener, removes it.
-            if (CollectionUtils.find(filteredNewSubs,
-                    it -> listener.equalsKey(it.first, it.second)) == null) {
+            if (!CollectionUtils.any(filteredNewSubs,
+                    it -> listener.equalsKey(it.first, it.second))) {
                 handleRemoveRatTypeListener(listener);
             }
         }
@@ -148,9 +149,10 @@
      * @return collapsed RatType for the given subscriberId
      */
     public int getRatTypeForSubscriberId(@NonNull String subscriberId) {
-        final RatTypeListener match = CollectionUtils.find(mRatListeners,
+        final int index = CollectionUtils.indexOf(mRatListeners,
                 it -> TextUtils.equals(subscriberId, it.mSubscriberId));
-        return match != null ? match.mLastCollapsedRatType : TelephonyManager.NETWORK_TYPE_UNKNOWN;
+        return index != -1 ? mRatListeners.get(index).mLastCollapsedRatType
+                : TelephonyManager.NETWORK_TYPE_UNKNOWN;
     }
 
     /**