diff --git a/api/current.txt b/api/current.txt
index 28fcac4..c082963 100755
--- a/api/current.txt
+++ b/api/current.txt
@@ -39439,7 +39439,7 @@
 
   public class CarrierIdentifier implements android.os.Parcelable {
     ctor public CarrierIdentifier(String, String, @Nullable String, @Nullable String, @Nullable String, @Nullable String);
-    ctor public CarrierIdentifier(String, String, @Nullable String, @Nullable String, @Nullable String, @Nullable String, int, int);
+    ctor public CarrierIdentifier(@NonNull String, @NonNull String, @Nullable String, @Nullable String, @Nullable String, @Nullable String, int, int);
     ctor public CarrierIdentifier(byte[], @Nullable String, @Nullable String);
     method public int describeContents();
     method public int getCarrierId();
diff --git a/core/java/android/service/carrier/CarrierIdentifier.java b/core/java/android/service/carrier/CarrierIdentifier.java
index 568ca0f..8c73a87 100644
--- a/core/java/android/service/carrier/CarrierIdentifier.java
+++ b/core/java/android/service/carrier/CarrierIdentifier.java
@@ -16,6 +16,7 @@
 
 package android.service.carrier;
 
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -74,7 +75,7 @@
      * @param preciseCarrierId precise carrier identifier
      * {@link TelephonyManager#getSimPreciseCarrierId()}
      */
-    public CarrierIdentifier(String mcc, String mnc, @Nullable String spn,
+    public CarrierIdentifier(@NonNull String mcc, @NonNull String mnc, @Nullable String spn,
                              @Nullable String imsi, @Nullable String gid1, @Nullable String gid2,
                              int carrierid, int preciseCarrierId) {
         mMcc = mcc;