Messaging: Nullability

Change-Id: I8bcde2a868a9c8989971d056be24ff4986e4f8f3

src/com/android/messaging/util/EmailAddress.java

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 The Android Open Source Project
+ * Copyright (C) 2024 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +17,8 @@
 
 package com.android.messaging.util;
 
+import androidx.annotation.NonNull;
+
 import com.google.common.base.CharMatcher;
 
 /**
@@ -104,6 +107,7 @@ public final class EmailAddress {
         return isValidInternal();
     }
 
+    @NonNull
     @Override
     public String toString() {
         return user + "@" + host;