diff --git a/api/current.txt b/api/current.txt
index 50253bd95b31b..b660b4fe05c79 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -53587,8 +53587,8 @@ package android.view.textclassifier {
     method @Nullable public CharSequence getText();
     method public void writeToParcel(android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.view.textclassifier.ConversationActions.Message> CREATOR;
-    field public static final android.app.Person PERSON_USER_OTHERS;
-    field public static final android.app.Person PERSON_USER_SELF;
+    field @NonNull public static final android.app.Person PERSON_USER_OTHERS;
+    field @NonNull public static final android.app.Person PERSON_USER_SELF;
   }
 
   public static final class ConversationActions.Message.Builder {
@@ -53617,7 +53617,7 @@ package android.view.textclassifier {
     ctor public ConversationActions.Request.Builder(@NonNull java.util.List<android.view.textclassifier.ConversationActions.Message>);
     method @NonNull public android.view.textclassifier.ConversationActions.Request build();
     method @NonNull public android.view.textclassifier.ConversationActions.Request.Builder setConversationId(@Nullable String);
-    method public android.view.textclassifier.ConversationActions.Request.Builder setHints(@Nullable java.util.List<java.lang.String>);
+    method @NonNull public android.view.textclassifier.ConversationActions.Request.Builder setHints(@Nullable java.util.List<java.lang.String>);
     method @NonNull public android.view.textclassifier.ConversationActions.Request.Builder setMaxSuggestions(@IntRange(from=0xffffffff) int);
     method @NonNull public android.view.textclassifier.ConversationActions.Request.Builder setTypeConfig(@Nullable android.view.textclassifier.TextClassifier.EntityConfig);
   }
@@ -53764,7 +53764,7 @@ package android.view.textclassifier {
     method public default boolean isDestroyed();
     method public default void onSelectionEvent(@NonNull android.view.textclassifier.SelectionEvent);
     method public default void onTextClassifierEvent(@NonNull android.view.textclassifier.TextClassifierEvent);
-    method @WorkerThread public default android.view.textclassifier.ConversationActions suggestConversationActions(@NonNull android.view.textclassifier.ConversationActions.Request);
+    method @WorkerThread @NonNull public default android.view.textclassifier.ConversationActions suggestConversationActions(@NonNull android.view.textclassifier.ConversationActions.Request);
     method @WorkerThread @NonNull public default android.view.textclassifier.TextSelection suggestSelection(@NonNull android.view.textclassifier.TextSelection.Request);
     method @WorkerThread @NonNull public default android.view.textclassifier.TextSelection suggestSelection(@NonNull CharSequence, @IntRange(from=0) int, @IntRange(from=0) int, @Nullable android.os.LocaleList);
     field public static final String EXTRA_FROM_TEXT_CLASSIFIER = "android.view.textclassifier.extra.FROM_TEXT_CLASSIFIER";
@@ -53809,7 +53809,7 @@ package android.view.textclassifier {
     method @NonNull public android.view.textclassifier.TextClassifier.EntityConfig build();
     method @NonNull public android.view.textclassifier.TextClassifier.EntityConfig.Builder includeTypesFromTextClassifier(boolean);
     method @NonNull public android.view.textclassifier.TextClassifier.EntityConfig.Builder setExcludedTypes(@Nullable java.util.Collection<java.lang.String>);
-    method public android.view.textclassifier.TextClassifier.EntityConfig.Builder setHints(java.util.Collection<java.lang.String>);
+    method @NonNull public android.view.textclassifier.TextClassifier.EntityConfig.Builder setHints(@Nullable java.util.Collection<java.lang.String>);
     method @NonNull public android.view.textclassifier.TextClassifier.EntityConfig.Builder setIncludedTypes(@Nullable java.util.Collection<java.lang.String>);
   }
 
@@ -53934,7 +53934,7 @@ package android.view.textclassifier {
     method @NonNull public android.view.textclassifier.TextLinks.Builder addLink(int, int, @NonNull java.util.Map<java.lang.String,java.lang.Float>, @NonNull android.os.Bundle);
     method @NonNull public android.view.textclassifier.TextLinks build();
     method @NonNull public android.view.textclassifier.TextLinks.Builder clearTextLinks();
-    method public android.view.textclassifier.TextLinks.Builder setExtras(@Nullable android.os.Bundle);
+    method @NonNull public android.view.textclassifier.TextLinks.Builder setExtras(@Nullable android.os.Bundle);
   }
 
   public static final class TextLinks.Request implements android.os.Parcelable {
@@ -53991,7 +53991,7 @@ package android.view.textclassifier {
     ctor public TextSelection.Builder(@IntRange(from=0) int, @IntRange(from=0) int);
     method @NonNull public android.view.textclassifier.TextSelection build();
     method @NonNull public android.view.textclassifier.TextSelection.Builder setEntityType(@NonNull String, @FloatRange(from=0.0, to=1.0) float);
-    method public android.view.textclassifier.TextSelection.Builder setExtras(@Nullable android.os.Bundle);
+    method @NonNull public android.view.textclassifier.TextSelection.Builder setExtras(@Nullable android.os.Bundle);
     method @NonNull public android.view.textclassifier.TextSelection.Builder setId(@Nullable String);
   }
 
@@ -54011,7 +54011,7 @@ package android.view.textclassifier {
     ctor public TextSelection.Request.Builder(@NonNull CharSequence, @IntRange(from=0) int, @IntRange(from=0) int);
     method @NonNull public android.view.textclassifier.TextSelection.Request build();
     method @NonNull public android.view.textclassifier.TextSelection.Request.Builder setDefaultLocales(@Nullable android.os.LocaleList);
-    method public android.view.textclassifier.TextSelection.Request.Builder setExtras(@Nullable android.os.Bundle);
+    method @NonNull public android.view.textclassifier.TextSelection.Request.Builder setExtras(@Nullable android.os.Bundle);
   }
 
 }
diff --git a/core/java/android/view/textclassifier/ConversationActions.java b/core/java/android/view/textclassifier/ConversationActions.java
index 9f9e66699d842..78ed9bf1071cf 100644
--- a/core/java/android/view/textclassifier/ConversationActions.java
+++ b/core/java/android/view/textclassifier/ConversationActions.java
@@ -109,6 +109,7 @@ public final class ConversationActions implements Parcelable {
          *
          * @see Builder#Builder(Person)
          */
+        @NonNull
         public static final Person PERSON_USER_SELF =
                 new Person.Builder()
                         .setKey("text-classifier-conversation-actions-user-self")
@@ -123,6 +124,7 @@ public final class ConversationActions implements Parcelable {
          *
          * @see Builder#Builder(Person)
          */
+        @NonNull
         public static final Person PERSON_USER_OTHERS =
                 new Person.Builder()
                         .setKey("text-classifier-conversation-actions-user-others")
@@ -465,6 +467,7 @@ public final class ConversationActions implements Parcelable {
              * Sets the hints to help text classifier to generate actions. It could be used to help
              * text classifier to infer what types of actions the caller may be interested in.
              */
+            @NonNull
             public Builder setHints(@Nullable @Hint List<String> hints) {
                 mHints = hints;
                 return this;
diff --git a/core/java/android/view/textclassifier/TextClassifier.java b/core/java/android/view/textclassifier/TextClassifier.java
index 23ce90e42b0cc..a4e550285c97d 100644
--- a/core/java/android/view/textclassifier/TextClassifier.java
+++ b/core/java/android/view/textclassifier/TextClassifier.java
@@ -353,6 +353,7 @@ public interface TextClassifier {
      * Suggests and returns a list of actions according to the given conversation.
      */
     @WorkerThread
+    @NonNull
     default ConversationActions suggestConversationActions(
             @NonNull ConversationActions.Request request) {
         Preconditions.checkNotNull(request);
@@ -609,7 +610,8 @@ public interface TextClassifier {
              * These hints will only be used if {@link #includeTypesFromTextClassifier} is
              * set to be true.
              */
-            public Builder setHints(Collection<String> hints) {
+            @NonNull
+            public Builder setHints(@Nullable Collection<String> hints) {
                 mHints = hints;
                 return this;
             }
diff --git a/core/java/android/view/textclassifier/TextLinks.java b/core/java/android/view/textclassifier/TextLinks.java
index d8216efc1ef24..cde27a08fc798 100644
--- a/core/java/android/view/textclassifier/TextLinks.java
+++ b/core/java/android/view/textclassifier/TextLinks.java
@@ -692,6 +692,7 @@ public final class TextLinks implements Parcelable {
          *
          * @return this builder
          */
+        @NonNull
         public Builder setExtras(@Nullable Bundle extras) {
             mExtras = extras;
             return this;
diff --git a/core/java/android/view/textclassifier/TextSelection.java b/core/java/android/view/textclassifier/TextSelection.java
index 52c532bb91f0d..52989397e4730 100644
--- a/core/java/android/view/textclassifier/TextSelection.java
+++ b/core/java/android/view/textclassifier/TextSelection.java
@@ -184,6 +184,7 @@ public final class TextSelection implements Parcelable {
          *
          * @return this builder
          */
+        @NonNull
         public Builder setExtras(@Nullable Bundle extras) {
             mExtras = extras;
             return this;
@@ -368,6 +369,7 @@ public final class TextSelection implements Parcelable {
              *
              * @return this builder
              */
+            @NonNull
             public Builder setExtras(@Nullable Bundle extras) {
                 mExtras = extras;
                 return this;