diff --git a/framework/src/android/net/NetworkInfo.java b/framework/src/android/net/NetworkInfo.java
index bb23494..433933f 100644
--- a/framework/src/android/net/NetworkInfo.java
+++ b/framework/src/android/net/NetworkInfo.java
@@ -179,21 +179,19 @@
 
     /** {@hide} */
     @UnsupportedAppUsage
-    public NetworkInfo(NetworkInfo source) {
-        if (source != null) {
-            synchronized (source) {
-                mNetworkType = source.mNetworkType;
-                mSubtype = source.mSubtype;
-                mTypeName = source.mTypeName;
-                mSubtypeName = source.mSubtypeName;
-                mState = source.mState;
-                mDetailedState = source.mDetailedState;
-                mReason = source.mReason;
-                mExtraInfo = source.mExtraInfo;
-                mIsFailover = source.mIsFailover;
-                mIsAvailable = source.mIsAvailable;
-                mIsRoaming = source.mIsRoaming;
-            }
+    public NetworkInfo(@NonNull NetworkInfo source) {
+        synchronized (source) {
+            mNetworkType = source.mNetworkType;
+            mSubtype = source.mSubtype;
+            mTypeName = source.mTypeName;
+            mSubtypeName = source.mSubtypeName;
+            mState = source.mState;
+            mDetailedState = source.mDetailedState;
+            mReason = source.mReason;
+            mExtraInfo = source.mExtraInfo;
+            mIsFailover = source.mIsFailover;
+            mIsAvailable = source.mIsAvailable;
+            mIsRoaming = source.mIsRoaming;
         }
     }
 
@@ -479,7 +477,7 @@
      * @param detailedState the {@link DetailedState}.
      * @param reason a {@code String} indicating the reason for the state change,
      * if one was supplied. May be {@code null}.
-     * @param extraInfo an optional {@code String} providing addditional network state
+     * @param extraInfo an optional {@code String} providing additional network state
      * information passed up from the lower networking layers.
      * @deprecated Use {@link NetworkCapabilities} instead.
      */
@@ -491,6 +489,11 @@
             this.mState = stateMap.get(detailedState);
             this.mReason = reason;
             this.mExtraInfo = extraInfo;
+            // Catch both the case where detailedState is null and the case where it's some
+            // unknown value
+            if (null == mState) {
+                throw new NullPointerException("Unknown DetailedState : " + detailedState);
+            }
         }
     }
 
diff --git a/tests/unit/java/com/android/server/connectivity/Nat464XlatTest.java b/tests/unit/java/com/android/server/connectivity/Nat464XlatTest.java
index f358726..aa4c4e3 100644
--- a/tests/unit/java/com/android/server/connectivity/Nat464XlatTest.java
+++ b/tests/unit/java/com/android/server/connectivity/Nat464XlatTest.java
@@ -109,8 +109,8 @@
 
         mNai.linkProperties = new LinkProperties();
         mNai.linkProperties.setInterfaceName(BASE_IFACE);
-        mNai.networkInfo = new NetworkInfo(null);
-        mNai.networkInfo.setType(ConnectivityManager.TYPE_WIFI);
+        mNai.networkInfo = new NetworkInfo(ConnectivityManager.TYPE_WIFI, 0 /* subtype */,
+                null /* typeName */, null /* subtypeName */);
         mNai.networkCapabilities = new NetworkCapabilities();
         markNetworkConnected();
         when(mNai.connService()).thenReturn(mConnectivity);