diff --git a/api/system-current.txt b/api/system-current.txt
index 3d164515790f0..984604805ff77 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -1172,7 +1172,7 @@ package android.app.usage {
     method @RequiresPermission(android.Manifest.permission.PACKAGE_USAGE_STATS) public int getAppStandbyBucket(String);
     method @RequiresPermission(android.Manifest.permission.PACKAGE_USAGE_STATS) public java.util.Map<java.lang.String,java.lang.Integer> getAppStandbyBuckets();
     method public int getUsageSource();
-    method @RequiresPermission(allOf={android.Manifest.permission.SUSPEND_APPS, android.Manifest.permission.OBSERVE_APP_USAGE}) public void registerAppUsageLimitObserver(int, @NonNull String[], long, @NonNull java.util.concurrent.TimeUnit, android.app.PendingIntent);
+    method @RequiresPermission(allOf={android.Manifest.permission.SUSPEND_APPS, android.Manifest.permission.OBSERVE_APP_USAGE}) public void registerAppUsageLimitObserver(int, @NonNull String[], long, @NonNull java.util.concurrent.TimeUnit, @Nullable android.app.PendingIntent);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_APP_USAGE) public void registerAppUsageObserver(int, @NonNull String[], long, @NonNull java.util.concurrent.TimeUnit, @NonNull android.app.PendingIntent);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_APP_USAGE) public void registerUsageSessionObserver(int, @NonNull String[], long, @NonNull java.util.concurrent.TimeUnit, long, @NonNull java.util.concurrent.TimeUnit, @NonNull android.app.PendingIntent, @Nullable android.app.PendingIntent);
     method public void reportUsageStart(@NonNull android.app.Activity, @NonNull String);
diff --git a/core/java/android/app/usage/UsageStatsManager.java b/core/java/android/app/usage/UsageStatsManager.java
index dc5bdc673249c..9c6bd927dd56c 100644
--- a/core/java/android/app/usage/UsageStatsManager.java
+++ b/core/java/android/app/usage/UsageStatsManager.java
@@ -779,7 +779,7 @@ public final class UsageStatsManager {
             android.Manifest.permission.SUSPEND_APPS,
             android.Manifest.permission.OBSERVE_APP_USAGE})
     public void registerAppUsageLimitObserver(int observerId, @NonNull String[] observedEntities,
-            long timeLimit, @NonNull TimeUnit timeUnit, PendingIntent callbackIntent) {
+            long timeLimit, @NonNull TimeUnit timeUnit, @Nullable PendingIntent callbackIntent) {
         try {
             mService.registerAppUsageLimitObserver(observerId, observedEntities,
                     timeUnit.toMillis(timeLimit), callbackIntent, mContext.getOpPackageName());