diff --git a/core/java/android/net/NattKeepalivePacketData.java b/core/java/android/net/NattKeepalivePacketData.java
index 3fb52f1..bd39c13 100644
--- a/core/java/android/net/NattKeepalivePacketData.java
+++ b/core/java/android/net/NattKeepalivePacketData.java
@@ -16,9 +16,11 @@
 
 package android.net;
 
-import static android.net.SocketKeepalive.ERROR_INVALID_IP_ADDRESS;
-import static android.net.SocketKeepalive.ERROR_INVALID_PORT;
+import static android.net.InvalidPacketException.ERROR_INVALID_IP_ADDRESS;
+import static android.net.InvalidPacketException.ERROR_INVALID_PORT;
 
+import android.annotation.NonNull;
+import android.annotation.SystemApi;
 import android.net.util.IpUtils;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -30,20 +32,22 @@
 import java.nio.ByteOrder;
 
 /** @hide */
+@SystemApi
 public final class NattKeepalivePacketData extends KeepalivePacketData implements Parcelable {
     private static final int IPV4_HEADER_LENGTH = 20;
     private static final int UDP_HEADER_LENGTH = 8;
 
     // This should only be constructed via static factory methods, such as
     // nattKeepalivePacket
-    private NattKeepalivePacketData(InetAddress srcAddress, int srcPort,
-            InetAddress dstAddress, int dstPort, byte[] data) throws
+    public NattKeepalivePacketData(@NonNull InetAddress srcAddress, int srcPort,
+            @NonNull InetAddress dstAddress, int dstPort, @NonNull byte[] data) throws
             InvalidPacketException {
         super(srcAddress, srcPort, dstAddress, dstPort, data);
     }
 
     /**
      * Factory method to create Nat-T keepalive packet structure.
+     * @hide
      */
     public static NattKeepalivePacketData nattKeepalivePacket(
             InetAddress srcAddress, int srcPort, InetAddress dstAddress, int dstPort)
@@ -87,7 +91,7 @@
     }
 
     /** Write to parcel */
-    public void writeToParcel(Parcel out, int flags) {
+    public void writeToParcel(@NonNull Parcel out, int flags) {
         out.writeString(srcAddress.getHostAddress());
         out.writeString(dstAddress.getHostAddress());
         out.writeInt(srcPort);
@@ -95,7 +99,7 @@
     }
 
     /** Parcelable Creator */
-    public static final Parcelable.Creator<NattKeepalivePacketData> CREATOR =
+    public static final @NonNull Parcelable.Creator<NattKeepalivePacketData> CREATOR =
             new Parcelable.Creator<NattKeepalivePacketData>() {
                 public NattKeepalivePacketData createFromParcel(Parcel in) {
                     final InetAddress srcAddress =