diff --git a/core/api/current.txt b/core/api/current.txt
index ec897e4a44379..cc17d0c76bdd5 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -13301,6 +13301,7 @@ package android.content.res {
     method public int describeContents();
     method public int diff(android.content.res.Configuration);
     method public boolean equals(android.content.res.Configuration);
+    method @NonNull public static android.content.res.Configuration generateDelta(@NonNull android.content.res.Configuration, @NonNull android.content.res.Configuration);
     method public int getLayoutDirection();
     method @NonNull public android.os.LocaleList getLocales();
     method public boolean isLayoutSizeAtLeast(int);
diff --git a/core/java/android/content/res/Configuration.java b/core/java/android/content/res/Configuration.java
index b66f048b829db..7deff7c78022b 100644
--- a/core/java/android/content/res/Configuration.java
+++ b/core/java/android/content/res/Configuration.java
@@ -2620,10 +2620,10 @@ public final class Configuration implements Parcelable, Comparable<Configuration
      * {@link #updateFrom(Configuration)} will treat it as a no-op and not update that member.
      *
      * This is fine for device configurations as no member is ever undefined.
-     * {@hide}
      */
-    @UnsupportedAppUsage
-    public static Configuration generateDelta(Configuration base, Configuration change) {
+    @NonNull
+    public static Configuration generateDelta(
+            @NonNull Configuration base, @NonNull Configuration change) {
         final Configuration delta = new Configuration();
         if (base.fontScale != change.fontScale) {
             delta.fontScale = change.fontScale;
diff --git a/packages/SettingsLib/src/com/android/settingslib/applications/InterestingConfigChanges.java b/packages/SettingsLib/src/com/android/settingslib/applications/InterestingConfigChanges.java
index c4cbc2b53a94d..5f2bef723cd90 100644
--- a/packages/SettingsLib/src/com/android/settingslib/applications/InterestingConfigChanges.java
+++ b/packages/SettingsLib/src/com/android/settingslib/applications/InterestingConfigChanges.java
@@ -16,10 +16,15 @@
 
 package com.android.settingslib.applications;
 
+import android.annotation.SuppressLint;
 import android.content.pm.ActivityInfo;
 import android.content.res.Configuration;
 import android.content.res.Resources;
 
+/**
+ * A class for applying config changes and determing if doing so resulting in any "interesting"
+ * changes.
+ */
 public class InterestingConfigChanges {
     private final Configuration mLastConfiguration = new Configuration();
     private final int mFlags;
@@ -35,6 +40,14 @@ public class InterestingConfigChanges {
         mFlags = flags;
     }
 
+    /**
+     * Applies the given config change and returns whether an "interesting" change happened.
+     *
+     * @param res The source of the new config to apply
+     *
+     * @return Whether interesting changes occurred
+     */
+    @SuppressLint("NewApi")
     public boolean applyNewConfig(Resources res) {
         int configChanges = mLastConfiguration.updateFrom(
                 Configuration.generateDelta(mLastConfiguration, res.getConfiguration()));