diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index e5802c2..1632235 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -4088,7 +4088,7 @@
     @SystemApi
     @TestApi
     @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
-    public void startCaptivePortalApp(Network network, Bundle appExtras) {
+    public void startCaptivePortalApp(@NonNull Network network, @NonNull Bundle appExtras) {
         try {
             mService.startCaptivePortalAppInternal(network, appExtras);
         } catch (RemoteException e) {
diff --git a/core/java/android/net/IpPrefix.java b/core/java/android/net/IpPrefix.java
index 175263f..b4f3a28 100644
--- a/core/java/android/net/IpPrefix.java
+++ b/core/java/android/net/IpPrefix.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.os.Parcel;
@@ -70,7 +71,7 @@
      *
      * @hide
      */
-    public IpPrefix(byte[] address, int prefixLength) {
+    public IpPrefix(@NonNull byte[] address, int prefixLength) {
         this.address = address.clone();
         this.prefixLength = prefixLength;
         checkAndMaskAddressAndPrefixLength();
@@ -87,7 +88,7 @@
      */
     @SystemApi
     @TestApi
-    public IpPrefix(InetAddress address, int prefixLength) {
+    public IpPrefix(@NonNull InetAddress address, int prefixLength) {
         // We don't reuse the (byte[], int) constructor because it calls clone() on the byte array,
         // which is unnecessary because getAddress() already returns a clone.
         this.address = address.getAddress();
@@ -106,7 +107,7 @@
      */
     @SystemApi
     @TestApi
-    public IpPrefix(String prefix) {
+    public IpPrefix(@NonNull String prefix) {
         // We don't reuse the (InetAddress, int) constructor because "error: call to this must be
         // first statement in constructor". We could factor out setting the member variables to an
         // init() method, but if we did, then we'd have to make the members non-final, or "error:
diff --git a/core/java/android/net/LinkAddress.java b/core/java/android/net/LinkAddress.java
index 8b01960..78b4665 100644
--- a/core/java/android/net/LinkAddress.java
+++ b/core/java/android/net/LinkAddress.java
@@ -26,6 +26,7 @@
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
@@ -107,8 +108,8 @@
      *
      * Per RFC 4193 section 8, fc00::/7 identifies these addresses.
      */
-    private boolean isIPv6ULA() {
-        if (isIPv6()) {
+    private boolean isIpv6ULA() {
+        if (isIpv6()) {
             byte[] bytes = address.getAddress();
             return ((bytes[0] & (byte)0xfe) == (byte)0xfc);
         }
@@ -121,17 +122,29 @@
      */
     @TestApi
     @SystemApi
-    public boolean isIPv6() {
+    public boolean isIpv6() {
         return address instanceof Inet6Address;
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return true if the address is IPv6.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean isIPv6() {
+        return isIpv6();
+    }
+
+    /**
      * @return true if the address is IPv4 or is a mapped IPv4 address.
      * @hide
      */
     @TestApi
     @SystemApi
-    public boolean isIPv4() {
+    public boolean isIpv4() {
         return address instanceof Inet4Address;
     }
 
@@ -217,7 +230,7 @@
      */
     @SystemApi
     @TestApi
-    public LinkAddress(String address, int flags, int scope) {
+    public LinkAddress(@NonNull String address, int flags, int scope) {
         // This may throw an IllegalArgumentException; catching it is the caller's responsibility.
         // TODO: consider rejecting mapped IPv4 addresses such as "::ffff:192.0.2.5/24".
         Pair<InetAddress, Integer> ipAndMask = NetworkUtils.parseIpAndMask(address);
@@ -276,7 +289,10 @@
      */
     @TestApi
     @SystemApi
-    public boolean isSameAddressAs(LinkAddress other) {
+    public boolean isSameAddressAs(@Nullable LinkAddress other) {
+        if (other == null) {
+            return false;
+        }
         return address.equals(other.address) && prefixLength == other.prefixLength;
     }
 
@@ -331,10 +347,10 @@
          * state has cleared either DAD has succeeded or failed, and both
          * flags are cleared regardless).
          */
-        return (scope == RT_SCOPE_UNIVERSE &&
-                !isIPv6ULA() &&
-                (flags & (IFA_F_DADFAILED | IFA_F_DEPRECATED)) == 0L &&
-                ((flags & IFA_F_TENTATIVE) == 0L || (flags & IFA_F_OPTIMISTIC) != 0L));
+        return (scope == RT_SCOPE_UNIVERSE
+                && !isIpv6ULA()
+                && (flags & (IFA_F_DADFAILED | IFA_F_DEPRECATED)) == 0L
+                && ((flags & IFA_F_TENTATIVE) == 0L || (flags & IFA_F_OPTIMISTIC) != 0L));
     }
 
     /**
diff --git a/core/java/android/net/LinkProperties.java b/core/java/android/net/LinkProperties.java
index 42db0fd..03d6d48 100644
--- a/core/java/android/net/LinkProperties.java
+++ b/core/java/android/net/LinkProperties.java
@@ -54,11 +54,11 @@
     // The interface described by the network link.
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
     private String mIfaceName;
-    private ArrayList<LinkAddress> mLinkAddresses = new ArrayList<>();
-    private ArrayList<InetAddress> mDnses = new ArrayList<>();
+    private final ArrayList<LinkAddress> mLinkAddresses = new ArrayList<>();
+    private final ArrayList<InetAddress> mDnses = new ArrayList<>();
     // PCSCF addresses are addresses of SIP proxies that only exist for the IMS core service.
-    private ArrayList<InetAddress> mPcscfs = new ArrayList<InetAddress>();
-    private ArrayList<InetAddress> mValidatedPrivateDnses = new ArrayList<>();
+    private final ArrayList<InetAddress> mPcscfs = new ArrayList<InetAddress>();
+    private final ArrayList<InetAddress> mValidatedPrivateDnses = new ArrayList<>();
     private boolean mUsePrivateDns;
     private String mPrivateDnsServerName;
     private String mDomains;
@@ -150,8 +150,8 @@
             // connections getting stuck until timeouts fire and other
             // baffling failures. Therefore, loss of either IPv4 or IPv6 on a
             // previously dual-stack network is deemed a lost of provisioning.
-            if ((before.isIPv4Provisioned() && !after.isIPv4Provisioned()) ||
-                (before.isIPv6Provisioned() && !after.isIPv6Provisioned())) {
+            if ((before.isIpv4Provisioned() && !after.isIpv4Provisioned())
+                    || (before.isIpv6Provisioned() && !after.isIpv6Provisioned())) {
                 return ProvisioningChange.LOST_PROVISIONING;
             }
             return ProvisioningChange.STILL_PROVISIONED;
@@ -165,9 +165,8 @@
     }
 
     /**
-     * @hide
+     * Constructs a new {@code LinkProperties} with default values.
      */
-    @SystemApi
     public LinkProperties() {
     }
 
@@ -176,7 +175,7 @@
      */
     @SystemApi
     @TestApi
-    public LinkProperties(LinkProperties source) {
+    public LinkProperties(@Nullable LinkProperties source) {
         if (source != null) {
             mIfaceName = source.mIfaceName;
             mLinkAddresses.addAll(source.mLinkAddresses);
@@ -202,10 +201,8 @@
      * will have their interface changed to match this new value.
      *
      * @param iface The name of the network interface used for this link.
-     * @hide
      */
-    @SystemApi
-    public void setInterfaceName(String iface) {
+    public void setInterfaceName(@Nullable String iface) {
         mIfaceName = iface;
         ArrayList<RouteInfo> newRoutes = new ArrayList<>(mRoutes.size());
         for (RouteInfo route : mRoutes) {
@@ -227,7 +224,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public List<String> getAllInterfaceNames() {
+    public @NonNull List<String> getAllInterfaceNames() {
         List<String> interfaceNames = new ArrayList<>(mStackedLinks.size() + 1);
         if (mIfaceName != null) interfaceNames.add(mIfaceName);
         for (LinkProperties stacked: mStackedLinks.values()) {
@@ -247,8 +244,8 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public List<InetAddress> getAddresses() {
-        List<InetAddress> addresses = new ArrayList<>();
+    public @NonNull List<InetAddress> getAddresses() {
+        final List<InetAddress> addresses = new ArrayList<>();
         for (LinkAddress linkAddress : mLinkAddresses) {
             addresses.add(linkAddress.getAddress());
         }
@@ -260,7 +257,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public List<InetAddress> getAllAddresses() {
+    public @NonNull List<InetAddress> getAllAddresses() {
         List<InetAddress> addresses = new ArrayList<>();
         for (LinkAddress linkAddress : mLinkAddresses) {
             addresses.add(linkAddress.getAddress());
@@ -289,7 +286,7 @@
      */
     @SystemApi
     @TestApi
-    public boolean addLinkAddress(LinkAddress address) {
+    public boolean addLinkAddress(@NonNull LinkAddress address) {
         if (address == null) {
             return false;
         }
@@ -318,7 +315,10 @@
      */
     @SystemApi
     @TestApi
-    public boolean removeLinkAddress(LinkAddress toRemove) {
+    public boolean removeLinkAddress(@NonNull LinkAddress toRemove) {
+        if (toRemove == null) {
+            return false;
+        }
         int i = findLinkAddressIndex(toRemove);
         if (i >= 0) {
             mLinkAddresses.remove(i);
@@ -333,7 +333,7 @@
      *
      * @return An unmodifiable {@link List} of {@link LinkAddress} for this link.
      */
-    public List<LinkAddress> getLinkAddresses() {
+    public @NonNull List<LinkAddress> getLinkAddresses() {
         return Collections.unmodifiableList(mLinkAddresses);
     }
 
@@ -356,10 +356,8 @@
      *
      * @param addresses The {@link Collection} of {@link LinkAddress} to set in this
      *                  object.
-     * @hide
      */
-    @SystemApi
-    public void setLinkAddresses(Collection<LinkAddress> addresses) {
+    public void setLinkAddresses(@NonNull Collection<LinkAddress> addresses) {
         mLinkAddresses.clear();
         for (LinkAddress address: addresses) {
             addLinkAddress(address);
@@ -375,7 +373,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean addDnsServer(InetAddress dnsServer) {
+    public boolean addDnsServer(@NonNull InetAddress dnsServer) {
         if (dnsServer != null && !mDnses.contains(dnsServer)) {
             mDnses.add(dnsServer);
             return true;
@@ -392,7 +390,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean removeDnsServer(InetAddress dnsServer) {
+    public boolean removeDnsServer(@NonNull InetAddress dnsServer) {
         if (dnsServer != null) {
             return mDnses.remove(dnsServer);
         }
@@ -404,10 +402,8 @@
      * the given {@link Collection} of {@link InetAddress} objects.
      *
      * @param dnsServers The {@link Collection} of DNS servers to set in this object.
-     * @hide
      */
-    @SystemApi
-    public void setDnsServers(Collection<InetAddress> dnsServers) {
+    public void setDnsServers(@NonNull Collection<InetAddress> dnsServers) {
         mDnses.clear();
         for (InetAddress dnsServer: dnsServers) {
             addDnsServer(dnsServer);
@@ -420,7 +416,7 @@
      * @return An unmodifiable {@link List} of {@link InetAddress} for DNS servers on
      *         this link.
      */
-    public List<InetAddress> getDnsServers() {
+    public @NonNull List<InetAddress> getDnsServers() {
         return Collections.unmodifiableList(mDnses);
     }
 
@@ -490,7 +486,7 @@
      * @return true if the DNS server was added, false if it was already present.
      * @hide
      */
-    public boolean addValidatedPrivateDnsServer(InetAddress dnsServer) {
+    public boolean addValidatedPrivateDnsServer(@NonNull InetAddress dnsServer) {
         if (dnsServer != null && !mValidatedPrivateDnses.contains(dnsServer)) {
             mValidatedPrivateDnses.add(dnsServer);
             return true;
@@ -506,11 +502,8 @@
      * @return true if the DNS server was removed, false if it did not exist.
      * @hide
      */
-    public boolean removeValidatedPrivateDnsServer(InetAddress dnsServer) {
-        if (dnsServer != null) {
-            return mValidatedPrivateDnses.remove(dnsServer);
-        }
-        return false;
+    public boolean removeValidatedPrivateDnsServer(@NonNull InetAddress dnsServer) {
+        return mValidatedPrivateDnses.remove(dnsServer);
     }
 
     /**
@@ -523,7 +516,7 @@
      */
     @TestApi
     @SystemApi
-    public void setValidatedPrivateDnsServers(Collection<InetAddress> dnsServers) {
+    public void setValidatedPrivateDnsServers(@NonNull Collection<InetAddress> dnsServers) {
         mValidatedPrivateDnses.clear();
         for (InetAddress dnsServer: dnsServers) {
             addValidatedPrivateDnsServer(dnsServer);
@@ -534,13 +527,13 @@
      * Returns all the {@link InetAddress} for validated private DNS servers on this link.
      * These are resolved from the private DNS server name.
      *
-     * @return An umodifiable {@link List} of {@link InetAddress} for validated private
+     * @return An unmodifiable {@link List} of {@link InetAddress} for validated private
      *         DNS servers on this link.
      * @hide
      */
     @TestApi
     @SystemApi
-    public List<InetAddress> getValidatedPrivateDnsServers() {
+    public @NonNull List<InetAddress> getValidatedPrivateDnsServers() {
         return Collections.unmodifiableList(mValidatedPrivateDnses);
     }
 
@@ -551,7 +544,7 @@
      * @return true if the PCSCF server was added, false otherwise.
      * @hide
      */
-    public boolean addPcscfServer(InetAddress pcscfServer) {
+    public boolean addPcscfServer(@NonNull InetAddress pcscfServer) {
         if (pcscfServer != null && !mPcscfs.contains(pcscfServer)) {
             mPcscfs.add(pcscfServer);
             return true;
@@ -562,27 +555,24 @@
     /**
      * Removes the given {@link InetAddress} from the list of PCSCF servers.
      *
-     * @param pcscf Server The {@link InetAddress} to remove from the list of PCSCF servers.
+     * @param pcscfServer The {@link InetAddress} to remove from the list of PCSCF servers.
      * @return true if the PCSCF server was removed, false otherwise.
      * @hide
      */
-    public boolean removePcscfServer(InetAddress pcscfServer) {
-        if (pcscfServer != null) {
-            return mPcscfs.remove(pcscfServer);
-        }
-        return false;
+    public boolean removePcscfServer(@NonNull InetAddress pcscfServer) {
+        return mPcscfs.remove(pcscfServer);
     }
 
     /**
      * Replaces the PCSCF servers in this {@code LinkProperties} with
      * the given {@link Collection} of {@link InetAddress} objects.
      *
-     * @param addresses The {@link Collection} of PCSCF servers to set in this object.
+     * @param pcscfServers The {@link Collection} of PCSCF servers to set in this object.
      * @hide
      */
     @SystemApi
     @TestApi
-    public void setPcscfServers(Collection<InetAddress> pcscfServers) {
+    public void setPcscfServers(@NonNull Collection<InetAddress> pcscfServers) {
         mPcscfs.clear();
         for (InetAddress pcscfServer: pcscfServers) {
             addPcscfServer(pcscfServer);
@@ -598,7 +588,7 @@
      */
     @SystemApi
     @TestApi
-    public List<InetAddress> getPcscfServers() {
+    public @NonNull List<InetAddress> getPcscfServers() {
         return Collections.unmodifiableList(mPcscfs);
     }
 
@@ -607,20 +597,18 @@
      *
      * @param domains A {@link String} listing in priority order the comma separated
      *                domains to search when resolving host names on this link.
-     * @hide
      */
-    @SystemApi
-    public void setDomains(String domains) {
+    public void setDomains(@Nullable String domains) {
         mDomains = domains;
     }
 
     /**
-     * Get the DNS domains search path set for this link.
+     * Get the DNS domains search path set for this link. May be {@code null} if not set.
      *
-     * @return A {@link String} containing the comma separated domains to search when resolving
-     *         host names on this link.
+     * @return A {@link String} containing the comma separated domains to search when resolving host
+     *         names on this link or {@code null}.
      */
-    public String getDomains() {
+    public @Nullable String getDomains() {
         return mDomains;
     }
 
@@ -630,9 +618,7 @@
      * 10000 will be ignored.
      *
      * @param mtu The MTU to use for this link.
-     * @hide
      */
-    @SystemApi
     public void setMtu(int mtu) {
         mMtu = mtu;
     }
@@ -657,20 +643,20 @@
      */
     @TestApi
     @SystemApi
-    public void setTcpBufferSizes(String tcpBufferSizes) {
+    public void setTcpBufferSizes(@Nullable String tcpBufferSizes) {
         mTcpBufferSizes = tcpBufferSizes;
     }
 
     /**
-     * Gets the tcp buffer sizes.
+     * Gets the tcp buffer sizes. May be {@code null} if not set.
      *
-     * @return the tcp buffer sizes to use when this link is the system default.
+     * @return the tcp buffer sizes to use when this link is the system default or {@code null}.
      *
      * @hide
      */
     @TestApi
     @SystemApi
-    public String getTcpBufferSizes() {
+    public @Nullable String getTcpBufferSizes() {
         return mTcpBufferSizes;
     }
 
@@ -690,23 +676,18 @@
      *
      * @param route A {@link RouteInfo} to add to this object.
      * @return {@code false} if the route was already present, {@code true} if it was added.
-     *
-     * @hide
      */
-    @SystemApi
-    public boolean addRoute(RouteInfo route) {
-        if (route != null) {
-            String routeIface = route.getInterface();
-            if (routeIface != null && !routeIface.equals(mIfaceName)) {
-                throw new IllegalArgumentException(
-                   "Route added with non-matching interface: " + routeIface +
-                   " vs. " + mIfaceName);
-            }
-            route = routeWithInterface(route);
-            if (!mRoutes.contains(route)) {
-                mRoutes.add(route);
-                return true;
-            }
+    public boolean addRoute(@NonNull RouteInfo route) {
+        String routeIface = route.getInterface();
+        if (routeIface != null && !routeIface.equals(mIfaceName)) {
+            throw new IllegalArgumentException(
+                    "Route added with non-matching interface: " + routeIface
+                            + " vs. " + mIfaceName);
+        }
+        route = routeWithInterface(route);
+        if (!mRoutes.contains(route)) {
+            mRoutes.add(route);
+            return true;
         }
         return false;
     }
@@ -722,10 +703,8 @@
      */
     @TestApi
     @SystemApi
-    public boolean removeRoute(RouteInfo route) {
-        return route != null &&
-                Objects.equals(mIfaceName, route.getInterface()) &&
-                mRoutes.remove(route);
+    public boolean removeRoute(@NonNull RouteInfo route) {
+        return Objects.equals(mIfaceName, route.getInterface()) && mRoutes.remove(route);
     }
 
     /**
@@ -733,7 +712,7 @@
      *
      * @return An unmodifiable {@link List} of {@link RouteInfo} for this link.
      */
-    public List<RouteInfo> getRoutes() {
+    public @NonNull List<RouteInfo> getRoutes() {
         return Collections.unmodifiableList(mRoutes);
     }
 
@@ -753,7 +732,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public List<RouteInfo> getAllRoutes() {
+    public @NonNull List<RouteInfo> getAllRoutes() {
         List<RouteInfo> routes = new ArrayList<>(mRoutes);
         for (LinkProperties stacked: mStackedLinks.values()) {
             routes.addAll(stacked.getAllRoutes());
@@ -767,26 +746,24 @@
      * not enforce it and applications may ignore them.
      *
      * @param proxy A {@link ProxyInfo} defining the HTTP Proxy to use on this link.
-     * @hide
      */
-    @SystemApi
-    public void setHttpProxy(ProxyInfo proxy) {
+    public void setHttpProxy(@Nullable ProxyInfo proxy) {
         mHttpProxy = proxy;
     }
 
     /**
      * Gets the recommended {@link ProxyInfo} (or {@code null}) set on this link.
      *
-     * @return The {@link ProxyInfo} set on this link
+     * @return The {@link ProxyInfo} set on this link or {@code null}.
      */
-    public ProxyInfo getHttpProxy() {
+    public @Nullable ProxyInfo getHttpProxy() {
         return mHttpProxy;
     }
 
     /**
      * Returns the NAT64 prefix in use on this link, if any.
      *
-     * @return the NAT64 prefix.
+     * @return the NAT64 prefix or {@code null}.
      * @hide
      */
     @SystemApi
@@ -799,14 +776,14 @@
      * Sets the NAT64 prefix in use on this link.
      *
      * Currently, only 96-bit prefixes (i.e., where the 32-bit IPv4 address is at the end of the
-     * 128-bit IPv6 address) are supported.
+     * 128-bit IPv6 address) are supported or {@code null} for no prefix.
      *
      * @param prefix the NAT64 prefix.
      * @hide
      */
     @SystemApi
     @TestApi
-    public void setNat64Prefix(IpPrefix prefix) {
+    public void setNat64Prefix(@Nullable IpPrefix prefix) {
         if (prefix != null && prefix.getPrefixLength() != 96) {
             throw new IllegalArgumentException("Only 96-bit prefixes are supported: " + prefix);
         }
@@ -818,15 +795,15 @@
      *
      * If there is already a stacked link with the same interface name as link,
      * that link is replaced with link. Otherwise, link is added to the list
-     * of stacked links. If link is null, nothing changes.
+     * of stacked links.
      *
      * @param link The link to add.
      * @return true if the link was stacked, false otherwise.
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean addStackedLink(LinkProperties link) {
-        if (link != null && link.getInterfaceName() != null) {
+    public boolean addStackedLink(@NonNull LinkProperties link) {
+        if (link.getInterfaceName() != null) {
             mStackedLinks.put(link.getInterfaceName(), link);
             return true;
         }
@@ -843,12 +820,9 @@
      * @return true if the link was removed, false otherwise.
      * @hide
      */
-    public boolean removeStackedLink(String iface) {
-        if (iface != null) {
-            LinkProperties removed = mStackedLinks.remove(iface);
-            return removed != null;
-        }
-        return false;
+    public boolean removeStackedLink(@NonNull String iface) {
+        LinkProperties removed = mStackedLinks.remove(iface);
+        return removed != null;
     }
 
     /**
@@ -860,7 +834,7 @@
         if (mStackedLinks.isEmpty()) {
             return Collections.emptyList();
         }
-        List<LinkProperties> stacked = new ArrayList<>();
+        final List<LinkProperties> stacked = new ArrayList<>();
         for (LinkProperties link : mStackedLinks.values()) {
             stacked.add(new LinkProperties(link));
         }
@@ -869,9 +843,7 @@
 
     /**
      * Clears this object to its initial state.
-     * @hide
      */
-    @SystemApi
     public void clear() {
         mIfaceName = null;
         mLinkAddresses.clear();
@@ -988,7 +960,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean hasIPv4Address() {
+    public boolean hasIpv4Address() {
         for (LinkAddress address : mLinkAddresses) {
             if (address.getAddress() instanceof Inet4Address) {
                 return true;
@@ -998,15 +970,27 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is an IPv4 address, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasIPv4Address() {
+        return hasIpv4Address();
+    }
+
+    /**
      * Returns true if this link or any of its stacked interfaces has an IPv4 address.
      *
      * @return {@code true} if there is an IPv4 address, {@code false} otherwise.
      */
-    private boolean hasIPv4AddressOnInterface(String iface) {
+    private boolean hasIpv4AddressOnInterface(String iface) {
         // mIfaceName can be null.
-        return (Objects.equals(iface, mIfaceName) && hasIPv4Address()) ||
-                (iface != null && mStackedLinks.containsKey(iface) &&
-                        mStackedLinks.get(iface).hasIPv4Address());
+        return (Objects.equals(iface, mIfaceName) && hasIpv4Address())
+                || (iface != null && mStackedLinks.containsKey(iface)
+                        && mStackedLinks.get(iface).hasIpv4Address());
     }
 
     /**
@@ -1017,7 +1001,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean hasGlobalIPv6Address() {
+    public boolean hasGlobalIpv6Address() {
         for (LinkAddress address : mLinkAddresses) {
           if (address.getAddress() instanceof Inet6Address && address.isGlobalPreferred()) {
             return true;
@@ -1027,13 +1011,25 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is a global preferred IPv6 address, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasGlobalIPv6Address() {
+        return hasGlobalIpv6Address();
+    }
+
+    /**
      * Returns true if this link has an IPv4 default route.
      *
      * @return {@code true} if there is an IPv4 default route, {@code false} otherwise.
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean hasIPv4DefaultRoute() {
+    public boolean hasIpv4DefaultRoute() {
         for (RouteInfo r : mRoutes) {
             if (r.isIPv4Default()) {
                 return true;
@@ -1043,6 +1039,18 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is an IPv4 default route, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasIPv4DefaultRoute() {
+        return hasIpv4DefaultRoute();
+    }
+
+    /**
      * Returns true if this link has an IPv6 default route.
      *
      * @return {@code true} if there is an IPv6 default route, {@code false} otherwise.
@@ -1050,7 +1058,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean hasIPv6DefaultRoute() {
+    public boolean hasIpv6DefaultRoute() {
         for (RouteInfo r : mRoutes) {
             if (r.isIPv6Default()) {
                 return true;
@@ -1060,13 +1068,25 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is an IPv6 default route, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasIPv6DefaultRoute() {
+        return hasIpv6DefaultRoute();
+    }
+
+    /**
      * Returns true if this link has an IPv4 DNS server.
      *
      * @return {@code true} if there is an IPv4 DNS server, {@code false} otherwise.
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean hasIPv4DnsServer() {
+    public boolean hasIpv4DnsServer() {
         for (InetAddress ia : mDnses) {
             if (ia instanceof Inet4Address) {
                 return true;
@@ -1076,13 +1096,25 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is an IPv4 DNS server, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasIPv4DnsServer() {
+        return hasIpv4DnsServer();
+    }
+
+    /**
      * Returns true if this link has an IPv6 DNS server.
      *
      * @return {@code true} if there is an IPv6 DNS server, {@code false} otherwise.
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean hasIPv6DnsServer() {
+    public boolean hasIpv6DnsServer() {
         for (InetAddress ia : mDnses) {
             if (ia instanceof Inet6Address) {
                 return true;
@@ -1092,12 +1124,24 @@
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if there is an IPv6 DNS server, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean hasIPv6DnsServer() {
+        return hasIpv6DnsServer();
+    }
+
+    /**
      * Returns true if this link has an IPv4 PCSCF server.
      *
      * @return {@code true} if there is an IPv4 PCSCF server, {@code false} otherwise.
      * @hide
      */
-    public boolean hasIPv4PcscfServer() {
+    public boolean hasIpv4PcscfServer() {
         for (InetAddress ia : mPcscfs) {
           if (ia instanceof Inet4Address) {
             return true;
@@ -1112,7 +1156,7 @@
      * @return {@code true} if there is an IPv6 PCSCF server, {@code false} otherwise.
      * @hide
      */
-    public boolean hasIPv6PcscfServer() {
+    public boolean hasIpv6PcscfServer() {
         for (InetAddress ia : mPcscfs) {
           if (ia instanceof Inet6Address) {
             return true;
@@ -1130,10 +1174,10 @@
      */
     @TestApi
     @SystemApi
-    public boolean isIPv4Provisioned() {
-        return (hasIPv4Address() &&
-                hasIPv4DefaultRoute() &&
-                hasIPv4DnsServer());
+    public boolean isIpv4Provisioned() {
+        return (hasIpv4Address()
+                && hasIpv4DefaultRoute()
+                && hasIpv4DnsServer());
     }
 
     /**
@@ -1145,13 +1189,26 @@
      */
     @TestApi
     @SystemApi
-    public boolean isIPv6Provisioned() {
-        return (hasGlobalIPv6Address() &&
-                hasIPv6DefaultRoute() &&
-                hasIPv6DnsServer());
+    public boolean isIpv6Provisioned() {
+        return (hasGlobalIpv6Address()
+                && hasIpv6DefaultRoute()
+                && hasIpv6DnsServer());
     }
 
     /**
+     * For backward compatibility.
+     * This was annotated with @UnsupportedAppUsage in P, so we can't remove the method completely
+     * just yet.
+     * @return {@code true} if the link is provisioned, {@code false} otherwise.
+     * @hide
+     */
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    public boolean isIPv6Provisioned() {
+        return isIpv6Provisioned();
+    }
+
+
+    /**
      * Returns true if this link is provisioned for global connectivity,
      * for at least one Internet Protocol family.
      *
@@ -1161,7 +1218,7 @@
     @TestApi
     @SystemApi
     public boolean isProvisioned() {
-        return (isIPv4Provisioned() || isIPv6Provisioned());
+        return (isIpv4Provisioned() || isIpv6Provisioned());
     }
 
     /**
@@ -1173,7 +1230,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean isReachable(InetAddress ip) {
+    public boolean isReachable(@NonNull InetAddress ip) {
         final List<RouteInfo> allRoutes = getAllRoutes();
         // If we don't have a route to this IP address, it's not reachable.
         final RouteInfo bestRoute = RouteInfo.selectBestRoute(allRoutes, ip);
@@ -1185,7 +1242,7 @@
 
         if (ip instanceof Inet4Address) {
             // For IPv4, it suffices for now to simply have any address.
-            return hasIPv4AddressOnInterface(bestRoute.getInterface());
+            return hasIpv4AddressOnInterface(bestRoute.getInterface());
         } else if (ip instanceof Inet6Address) {
             if (ip.isLinkLocalAddress()) {
                 // For now, just make sure link-local destinations have
@@ -1196,7 +1253,7 @@
                 // For non-link-local destinations check that either the best route
                 // is directly connected or that some global preferred address exists.
                 // TODO: reconsider all cases (disconnected ULA networks, ...).
-                return (!bestRoute.hasGateway() || hasGlobalIPv6Address());
+                return (!bestRoute.hasGateway() || hasGlobalIpv6Address());
             }
         }
 
@@ -1211,7 +1268,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean isIdenticalInterfaceName(LinkProperties target) {
+    public boolean isIdenticalInterfaceName(@NonNull LinkProperties target) {
         return TextUtils.equals(getInterfaceName(), target.getInterfaceName());
     }
 
@@ -1223,7 +1280,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean isIdenticalAddresses(LinkProperties target) {
+    public boolean isIdenticalAddresses(@NonNull LinkProperties target) {
         Collection<InetAddress> targetAddresses = target.getAddresses();
         Collection<InetAddress> sourceAddresses = getAddresses();
         return (sourceAddresses.size() == targetAddresses.size()) ?
@@ -1238,7 +1295,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean isIdenticalDnses(LinkProperties target) {
+    public boolean isIdenticalDnses(@NonNull LinkProperties target) {
         Collection<InetAddress> targetDnses = target.getDnsServers();
         String targetDomains = target.getDomains();
         if (mDomains == null) {
@@ -1258,7 +1315,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalPrivateDns(LinkProperties target) {
+    public boolean isIdenticalPrivateDns(@NonNull LinkProperties target) {
         return (isPrivateDnsActive() == target.isPrivateDnsActive()
                 && TextUtils.equals(getPrivateDnsServerName(),
                 target.getPrivateDnsServerName()));
@@ -1272,7 +1329,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalValidatedPrivateDnses(LinkProperties target) {
+    public boolean isIdenticalValidatedPrivateDnses(@NonNull LinkProperties target) {
         Collection<InetAddress> targetDnses = target.getValidatedPrivateDnsServers();
         return (mValidatedPrivateDnses.size() == targetDnses.size())
                 ? mValidatedPrivateDnses.containsAll(targetDnses) : false;
@@ -1285,7 +1342,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalPcscfs(LinkProperties target) {
+    public boolean isIdenticalPcscfs(@NonNull LinkProperties target) {
         Collection<InetAddress> targetPcscfs = target.getPcscfServers();
         return (mPcscfs.size() == targetPcscfs.size()) ?
                     mPcscfs.containsAll(targetPcscfs) : false;
@@ -1299,7 +1356,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean isIdenticalRoutes(LinkProperties target) {
+    public boolean isIdenticalRoutes(@NonNull LinkProperties target) {
         Collection<RouteInfo> targetRoutes = target.getRoutes();
         return (mRoutes.size() == targetRoutes.size()) ?
                 mRoutes.containsAll(targetRoutes) : false;
@@ -1313,7 +1370,7 @@
      * @hide
      */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
-    public boolean isIdenticalHttpProxy(LinkProperties target) {
+    public boolean isIdenticalHttpProxy(@NonNull LinkProperties target) {
         return getHttpProxy() == null ? target.getHttpProxy() == null :
                 getHttpProxy().equals(target.getHttpProxy());
     }
@@ -1326,7 +1383,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public boolean isIdenticalStackedLinks(LinkProperties target) {
+    public boolean isIdenticalStackedLinks(@NonNull LinkProperties target) {
         if (!mStackedLinks.keySet().equals(target.mStackedLinks.keySet())) {
             return false;
         }
@@ -1347,7 +1404,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalMtu(LinkProperties target) {
+    public boolean isIdenticalMtu(@NonNull LinkProperties target) {
         return getMtu() == target.getMtu();
     }
 
@@ -1358,7 +1415,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalTcpBufferSizes(LinkProperties target) {
+    public boolean isIdenticalTcpBufferSizes(@NonNull LinkProperties target) {
         return Objects.equals(mTcpBufferSizes, target.mTcpBufferSizes);
     }
 
@@ -1369,7 +1426,7 @@
      * @return {@code true} if both are identical, {@code false} otherwise.
      * @hide
      */
-    public boolean isIdenticalNat64Prefix(LinkProperties target) {
+    public boolean isIdenticalNat64Prefix(@NonNull LinkProperties target) {
         return Objects.equals(mNat64Prefix, target.mNat64Prefix);
     }
 
@@ -1421,7 +1478,7 @@
      * @return the differences between the addresses.
      * @hide
      */
-    public CompareResult<LinkAddress> compareAddresses(LinkProperties target) {
+    public @NonNull CompareResult<LinkAddress> compareAddresses(@Nullable LinkProperties target) {
         /*
          * Duplicate the LinkAddresses into removed, we will be removing
          * address which are common between mLinkAddresses and target
@@ -1441,7 +1498,7 @@
      * @return the differences between the DNS addresses.
      * @hide
      */
-    public CompareResult<InetAddress> compareDnses(LinkProperties target) {
+    public @NonNull CompareResult<InetAddress> compareDnses(@Nullable LinkProperties target) {
         /*
          * Duplicate the InetAddresses into removed, we will be removing
          * dns address which are common between mDnses and target
@@ -1460,7 +1517,8 @@
      * @return the differences between the DNS addresses.
      * @hide
      */
-    public CompareResult<InetAddress> compareValidatedPrivateDnses(LinkProperties target) {
+    public @NonNull CompareResult<InetAddress> compareValidatedPrivateDnses(
+            @Nullable LinkProperties target) {
         return new CompareResult<>(mValidatedPrivateDnses,
                 target != null ? target.getValidatedPrivateDnsServers() : null);
     }
@@ -1473,7 +1531,7 @@
      * @return the differences between the routes.
      * @hide
      */
-    public CompareResult<RouteInfo> compareAllRoutes(LinkProperties target) {
+    public @NonNull CompareResult<RouteInfo> compareAllRoutes(@Nullable LinkProperties target) {
         /*
          * Duplicate the RouteInfos into removed, we will be removing
          * routes which are common between mRoutes and target
@@ -1491,7 +1549,8 @@
      * @return the differences between the interface names.
      * @hide
      */
-    public CompareResult<String> compareAllInterfaceNames(LinkProperties target) {
+    public @NonNull CompareResult<String> compareAllInterfaceNames(
+            @Nullable LinkProperties target) {
         /*
          * Duplicate the interface names into removed, we will be removing
          * interface names which are common between this and target
diff --git a/core/java/android/net/Network.java b/core/java/android/net/Network.java
index e04b5fc..09a86fc 100644
--- a/core/java/android/net/Network.java
+++ b/core/java/android/net/Network.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
@@ -125,7 +126,7 @@
      */
     @SystemApi
     @TestApi
-    public Network(Network that) {
+    public Network(@NonNull Network that) {
         this(that.netId, that.mPrivateDnsBypass);
     }
 
@@ -163,7 +164,7 @@
      */
     @TestApi
     @SystemApi
-    public Network getPrivateDnsBypassingCopy() {
+    public @NonNull Network getPrivateDnsBypassingCopy() {
         return new Network(netId, true);
     }
 
diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index e1cfe99..99375f8 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
@@ -91,7 +92,7 @@
      * Set all contents of this object to the contents of a NetworkCapabilities.
      * @hide
      */
-    public void set(NetworkCapabilities nc) {
+    public void set(@NonNull NetworkCapabilities nc) {
         mNetworkCapabilities = nc.mNetworkCapabilities;
         mTransportTypes = nc.mTransportTypes;
         mLinkUpBandwidthKbps = nc.mLinkUpBandwidthKbps;
@@ -405,7 +406,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public NetworkCapabilities addCapability(@NetCapability int capability) {
+    public @NonNull NetworkCapabilities addCapability(@NetCapability int capability) {
         checkValidCapability(capability);
         mNetworkCapabilities |= 1 << capability;
         mUnwantedNetworkCapabilities &= ~(1 << capability);  // remove from unwanted capability list
@@ -442,7 +443,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public NetworkCapabilities removeCapability(@NetCapability int capability) {
+    public @NonNull NetworkCapabilities removeCapability(@NetCapability int capability) {
         checkValidCapability(capability);
         final long mask = ~(1 << capability);
         mNetworkCapabilities &= mask;
@@ -456,7 +457,8 @@
      *
      * @hide
      */
-    public NetworkCapabilities setCapability(@NetCapability int capability, boolean value) {
+    public @NonNull NetworkCapabilities setCapability(@NetCapability int capability,
+            boolean value) {
         if (value) {
             addCapability(capability);
         } else {
@@ -534,7 +536,7 @@
     }
 
     /** Note this method may result in having the same capability in wanted and unwanted lists. */
-    private void combineNetCapabilities(NetworkCapabilities nc) {
+    private void combineNetCapabilities(@NonNull NetworkCapabilities nc) {
         this.mNetworkCapabilities |= nc.mNetworkCapabilities;
         this.mUnwantedNetworkCapabilities |= nc.mUnwantedNetworkCapabilities;
     }
@@ -546,7 +548,7 @@
      *
      * @hide
      */
-    public String describeFirstNonRequestableCapability() {
+    public @Nullable String describeFirstNonRequestableCapability() {
         final long nonRequestable = (mNetworkCapabilities | mUnwantedNetworkCapabilities)
                 & NON_REQUESTABLE_CAPABILITIES;
 
@@ -558,7 +560,8 @@
         return null;
     }
 
-    private boolean satisfiedByNetCapabilities(NetworkCapabilities nc, boolean onlyImmutable) {
+    private boolean satisfiedByNetCapabilities(@NonNull NetworkCapabilities nc,
+            boolean onlyImmutable) {
         long requestedCapabilities = mNetworkCapabilities;
         long requestedUnwantedCapabilities = mUnwantedNetworkCapabilities;
         long providedCapabilities = nc.mNetworkCapabilities;
@@ -572,12 +575,12 @@
     }
 
     /** @hide */
-    public boolean equalsNetCapabilities(NetworkCapabilities nc) {
+    public boolean equalsNetCapabilities(@NonNull NetworkCapabilities nc) {
         return (nc.mNetworkCapabilities == this.mNetworkCapabilities)
                 && (nc.mUnwantedNetworkCapabilities == this.mUnwantedNetworkCapabilities);
     }
 
-    private boolean equalsNetCapabilitiesRequestable(NetworkCapabilities that) {
+    private boolean equalsNetCapabilitiesRequestable(@NonNull NetworkCapabilities that) {
         return ((this.mNetworkCapabilities & ~NON_REQUESTABLE_CAPABILITIES) ==
                 (that.mNetworkCapabilities & ~NON_REQUESTABLE_CAPABILITIES))
                 && ((this.mUnwantedNetworkCapabilities & ~NON_REQUESTABLE_CAPABILITIES) ==
@@ -713,7 +716,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public NetworkCapabilities addTransportType(@Transport int transportType) {
+    public @NonNull NetworkCapabilities addTransportType(@Transport int transportType) {
         checkValidTransportType(transportType);
         mTransportTypes |= 1 << transportType;
         setNetworkSpecifier(mNetworkSpecifier); // used for exception checking
@@ -727,7 +730,7 @@
      * @return This NetworkCapabilities instance, to facilitate chaining.
      * @hide
      */
-    public NetworkCapabilities removeTransportType(@Transport int transportType) {
+    public @NonNull NetworkCapabilities removeTransportType(@Transport int transportType) {
         checkValidTransportType(transportType);
         mTransportTypes &= ~(1 << transportType);
         setNetworkSpecifier(mNetworkSpecifier); // used for exception checking
@@ -740,7 +743,8 @@
      *
      * @hide
      */
-    public NetworkCapabilities setTransportType(@Transport int transportType, boolean value) {
+    public @NonNull NetworkCapabilities setTransportType(@Transport int transportType,
+            boolean value) {
         if (value) {
             addTransportType(transportType);
         } else {
@@ -757,7 +761,7 @@
      */
     @TestApi
     @SystemApi
-    public @Transport int[] getTransportTypes() {
+    @NonNull public @Transport int[] getTransportTypes() {
         return BitUtils.unpackBits(mTransportTypes);
     }
 
@@ -847,7 +851,7 @@
      * @param upKbps the estimated first hop upstream (device to network) bandwidth.
      * @hide
      */
-    public NetworkCapabilities setLinkUpstreamBandwidthKbps(int upKbps) {
+    public @NonNull NetworkCapabilities setLinkUpstreamBandwidthKbps(int upKbps) {
         mLinkUpBandwidthKbps = upKbps;
         return this;
     }
@@ -877,7 +881,7 @@
      * @param downKbps the estimated first hop downstream (network to device) bandwidth.
      * @hide
      */
-    public NetworkCapabilities setLinkDownstreamBandwidthKbps(int downKbps) {
+    public @NonNull NetworkCapabilities setLinkDownstreamBandwidthKbps(int downKbps) {
         mLinkDownBandwidthKbps = downKbps;
         return this;
     }
@@ -936,7 +940,7 @@
      * @return This NetworkCapabilities instance, to facilitate chaining.
      * @hide
      */
-    public NetworkCapabilities setNetworkSpecifier(NetworkSpecifier networkSpecifier) {
+    public @NonNull NetworkCapabilities setNetworkSpecifier(NetworkSpecifier networkSpecifier) {
         if (networkSpecifier != null && Long.bitCount(mTransportTypes) != 1) {
             throw new IllegalStateException("Must have a single transport specified to use " +
                     "setNetworkSpecifier");
@@ -955,20 +959,20 @@
      * @return This NetworkCapabilities instance, to facilitate chaining.
      * @hide
      */
-    public NetworkCapabilities setTransportInfo(TransportInfo transportInfo) {
+    public @NonNull NetworkCapabilities setTransportInfo(TransportInfo transportInfo) {
         mTransportInfo = transportInfo;
         return this;
     }
 
     /**
-     * Gets the optional bearer specific network specifier.
+     * Gets the optional bearer specific network specifier. May be {@code null} if not set.
      *
      * @return The optional {@link NetworkSpecifier} specifying the bearer specific network
-     *         specifier. See {@link #setNetworkSpecifier}.
+     *         specifier or {@code null}. See {@link #setNetworkSpecifier}.
      * @hide
      */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
-    public NetworkSpecifier getNetworkSpecifier() {
+    public @Nullable NetworkSpecifier getNetworkSpecifier() {
         return mNetworkSpecifier;
     }
 
@@ -1015,8 +1019,6 @@
     /**
      * Magic value that indicates no signal strength provided. A request specifying this value is
      * always satisfied.
-     *
-     * @hide
      */
     public static final int SIGNAL_STRENGTH_UNSPECIFIED = Integer.MIN_VALUE;
 
@@ -1024,7 +1026,7 @@
      * Signal strength. This is a signed integer, and higher values indicate better signal.
      * The exact units are bearer-dependent. For example, Wi-Fi uses RSSI.
      */
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
     private int mSignalStrength = SIGNAL_STRENGTH_UNSPECIFIED;
 
     /**
@@ -1041,7 +1043,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public NetworkCapabilities setSignalStrength(int signalStrength) {
+    public @NonNull NetworkCapabilities setSignalStrength(int signalStrength) {
         mSignalStrength = signalStrength;
         return this;
     }
@@ -1060,9 +1062,7 @@
      * Retrieves the signal strength.
      *
      * @return The bearer-specific signal strength.
-     * @hide
      */
-    @SystemApi
     public int getSignalStrength() {
         return mSignalStrength;
     }
@@ -1120,7 +1120,7 @@
      * Convenience method to set the UIDs this network applies to to a single UID.
      * @hide
      */
-    public NetworkCapabilities setSingleUid(int uid) {
+    public @NonNull NetworkCapabilities setSingleUid(int uid) {
         final ArraySet<UidRange> identity = new ArraySet<>(1);
         identity.add(new UidRange(uid, uid));
         setUids(identity);
@@ -1132,7 +1132,7 @@
      * This makes a copy of the set so that callers can't modify it after the call.
      * @hide
      */
-    public NetworkCapabilities setUids(Set<UidRange> uids) {
+    public @NonNull NetworkCapabilities setUids(Set<UidRange> uids) {
         if (null == uids) {
             mUids = null;
         } else {
@@ -1146,7 +1146,7 @@
      * This returns a copy of the set so that callers can't modify the original object.
      * @hide
      */
-    public Set<UidRange> getUids() {
+    public @Nullable Set<UidRange> getUids() {
         return null == mUids ? null : new ArraySet<>(mUids);
     }
 
@@ -1179,7 +1179,7 @@
      * @hide
      */
     @VisibleForTesting
-    public boolean equalsUids(NetworkCapabilities nc) {
+    public boolean equalsUids(@NonNull NetworkCapabilities nc) {
         Set<UidRange> comparedUids = nc.mUids;
         if (null == comparedUids) return null == mUids;
         if (null == mUids) return false;
@@ -1212,7 +1212,7 @@
      * @see #appliesToUid
      * @hide
      */
-    public boolean satisfiedByUids(NetworkCapabilities nc) {
+    public boolean satisfiedByUids(@NonNull NetworkCapabilities nc) {
         if (null == nc.mUids || null == mUids) return true; // The network satisfies everything.
         for (UidRange requiredRange : mUids) {
             if (requiredRange.contains(nc.mEstablishingVpnAppUid)) return true;
@@ -1232,7 +1232,7 @@
      * @hide
      */
     @VisibleForTesting
-    public boolean appliesToUidRange(UidRange requiredRange) {
+    public boolean appliesToUidRange(@Nullable UidRange requiredRange) {
         if (null == mUids) return true;
         for (UidRange uidRange : mUids) {
             if (uidRange.containsRange(requiredRange)) {
@@ -1247,7 +1247,7 @@
      * NetworkCapabilities apply to.
      * nc is assumed nonnull.
      */
-    private void combineUids(NetworkCapabilities nc) {
+    private void combineUids(@NonNull NetworkCapabilities nc) {
         if (null == nc.mUids || null == mUids) {
             mUids = null;
             return;
@@ -1268,7 +1268,7 @@
      * Sets the SSID of this network.
      * @hide
      */
-    public NetworkCapabilities setSSID(String ssid) {
+    public @NonNull NetworkCapabilities setSSID(@Nullable String ssid) {
         mSSID = ssid;
         return this;
     }
@@ -1277,7 +1277,7 @@
      * Gets the SSID of this network, or null if none or unknown.
      * @hide
      */
-    public String getSSID() {
+    public @Nullable String getSSID() {
         return mSSID;
     }
 
@@ -1285,7 +1285,7 @@
      * Tests if the SSID of this network is the same as the SSID of the passed network.
      * @hide
      */
-    public boolean equalsSSID(NetworkCapabilities nc) {
+    public boolean equalsSSID(@NonNull NetworkCapabilities nc) {
         return Objects.equals(mSSID, nc.mSSID);
     }
 
@@ -1293,7 +1293,7 @@
      * Check if the SSID requirements of this object are matched by the passed object.
      * @hide
      */
-    public boolean satisfiedBySSID(NetworkCapabilities nc) {
+    public boolean satisfiedBySSID(@NonNull NetworkCapabilities nc) {
         return mSSID == null || mSSID.equals(nc.mSSID);
     }
 
@@ -1304,7 +1304,7 @@
      * equal.
      * @hide
      */
-    private void combineSSIDs(NetworkCapabilities nc) {
+    private void combineSSIDs(@NonNull NetworkCapabilities nc) {
         if (mSSID != null && !mSSID.equals(nc.mSSID)) {
             throw new IllegalStateException("Can't combine two SSIDs");
         }
@@ -1319,7 +1319,7 @@
      * both lists will never be satisfied.
      * @hide
      */
-    public void combineCapabilities(NetworkCapabilities nc) {
+    public void combineCapabilities(@NonNull NetworkCapabilities nc) {
         combineNetCapabilities(nc);
         combineTransportTypes(nc);
         combineLinkBandwidths(nc);
@@ -1359,7 +1359,7 @@
      */
     @TestApi
     @SystemApi
-    public boolean satisfiedByNetworkCapabilities(NetworkCapabilities nc) {
+    public boolean satisfiedByNetworkCapabilities(@Nullable NetworkCapabilities nc) {
         return satisfiedByNetworkCapabilities(nc, false);
     }
 
@@ -1370,7 +1370,7 @@
      *
      * @hide
      */
-    public boolean satisfiedByImmutableNetworkCapabilities(NetworkCapabilities nc) {
+    public boolean satisfiedByImmutableNetworkCapabilities(@Nullable NetworkCapabilities nc) {
         return satisfiedByNetworkCapabilities(nc, true);
     }
 
@@ -1381,7 +1381,7 @@
      *
      * @hide
      */
-    public String describeImmutableDifferences(NetworkCapabilities that) {
+    public String describeImmutableDifferences(@Nullable NetworkCapabilities that) {
         if (that == null) {
             return "other NetworkCapabilities was null";
         }
@@ -1420,7 +1420,7 @@
      *
      * @hide
      */
-    public boolean equalRequestableCapabilities(NetworkCapabilities nc) {
+    public boolean equalRequestableCapabilities(@Nullable NetworkCapabilities nc) {
         if (nc == null) return false;
         return (equalsNetCapabilitiesRequestable(nc) &&
                 equalsTransportTypes(nc) &&
@@ -1428,7 +1428,7 @@
     }
 
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (obj == null || (obj instanceof NetworkCapabilities == false)) return false;
         NetworkCapabilities that = (NetworkCapabilities) obj;
         return (equalsNetCapabilities(that)
@@ -1502,7 +1502,7 @@
         };
 
     @Override
-    public String toString() {
+    public @NonNull String toString() {
         final StringBuilder sb = new StringBuilder("[");
         if (0 != mTransportTypes) {
             sb.append(" Transports: ");
@@ -1561,8 +1561,8 @@
     /**
      * @hide
      */
-    public static void appendStringRepresentationOfBitMaskToStringBuilder(StringBuilder sb,
-            long bitMask, NameOf nameFetcher, String separator) {
+    public static void appendStringRepresentationOfBitMaskToStringBuilder(@NonNull StringBuilder sb,
+            long bitMask, @NonNull NameOf nameFetcher, @NonNull String separator) {
         int bitPos = 0;
         boolean firstElementAdded = false;
         while (bitMask != 0) {
@@ -1580,7 +1580,7 @@
     }
 
     /** @hide */
-    public void writeToProto(ProtoOutputStream proto, long fieldId) {
+    public void writeToProto(@NonNull ProtoOutputStream proto, long fieldId) {
         final long token = proto.start(fieldId);
 
         for (int transport : getTransportTypes()) {
@@ -1610,7 +1610,7 @@
     /**
      * @hide
      */
-    public static String capabilityNamesOf(@NetCapability int[] capabilities) {
+    public static @NonNull String capabilityNamesOf(@Nullable @NetCapability int[] capabilities) {
         StringJoiner joiner = new StringJoiner("|");
         if (capabilities != null) {
             for (int c : capabilities) {
@@ -1623,7 +1623,7 @@
     /**
      * @hide
      */
-    public static String capabilityNameOf(@NetCapability int capability) {
+    public static @NonNull String capabilityNameOf(@NetCapability int capability) {
         switch (capability) {
             case NET_CAPABILITY_MMS:                  return "MMS";
             case NET_CAPABILITY_SUPL:                 return "SUPL";
@@ -1658,7 +1658,7 @@
      * @hide
      */
     @UnsupportedAppUsage
-    public static String transportNamesOf(@Transport int[] types) {
+    public static @NonNull String transportNamesOf(@Nullable @Transport int[] types) {
         StringJoiner joiner = new StringJoiner("|");
         if (types != null) {
             for (int t : types) {
@@ -1671,7 +1671,7 @@
     /**
      * @hide
      */
-    public static String transportNameOf(@Transport int transport) {
+    public static @NonNull String transportNameOf(@Transport int transport) {
         if (!isValidTransport(transport)) {
             return "UNKNOWN";
         }
diff --git a/core/java/android/net/NetworkInfo.java b/core/java/android/net/NetworkInfo.java
index 89d9961..8fb5a20 100644
--- a/core/java/android/net/NetworkInfo.java
+++ b/core/java/android/net/NetworkInfo.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.NonNull;
 import android.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -138,7 +139,9 @@
     private int mSubtype;
     private String mTypeName;
     private String mSubtypeName;
+    @NonNull
     private State mState;
+    @NonNull
     private DetailedState mDetailedState;
     private String mReason;
     private String mExtraInfo;
@@ -451,7 +454,7 @@
      *             the device and let apps react more easily and quickly to changes.
      */
     @Deprecated
-    public DetailedState getDetailedState() {
+    public @NonNull DetailedState getDetailedState() {
         synchronized (this) {
             return mDetailedState;
         }
diff --git a/core/java/android/net/NetworkRequest.java b/core/java/android/net/NetworkRequest.java
index 9508217..3a41a07 100644
--- a/core/java/android/net/NetworkRequest.java
+++ b/core/java/android/net/NetworkRequest.java
@@ -347,7 +347,7 @@
          * @hide
          */
         @SystemApi
-        public Builder setSignalStrength(int signalStrength) {
+        public @NonNull Builder setSignalStrength(int signalStrength) {
             mNetworkCapabilities.setSignalStrength(signalStrength);
             return this;
         }
diff --git a/core/java/android/net/RouteInfo.java b/core/java/android/net/RouteInfo.java
index 5c0f758..24d9b8e 100644
--- a/core/java/android/net/RouteInfo.java
+++ b/core/java/android/net/RouteInfo.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
@@ -112,7 +113,8 @@
      */
     @SystemApi
     @TestApi
-    public RouteInfo(IpPrefix destination, InetAddress gateway, String iface, int type) {
+    public RouteInfo(@Nullable IpPrefix destination, @Nullable InetAddress gateway,
+            @Nullable String iface, int type) {
         switch (type) {
             case RTN_UNICAST:
             case RTN_UNREACHABLE:
diff --git a/core/java/android/net/apf/ApfCapabilities.java b/core/java/android/net/apf/ApfCapabilities.java
index d6023d7..17a03c7 100644
--- a/core/java/android/net/apf/ApfCapabilities.java
+++ b/core/java/android/net/apf/ApfCapabilities.java
@@ -16,6 +16,7 @@
 
 package android.net.apf;
 
+import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.content.Context;
@@ -115,14 +116,14 @@
     /**
      * @return Whether the APF Filter in the device should filter out IEEE 802.3 Frames.
      */
-    public static boolean getApfDrop8023Frames(Context context) {
+    public static boolean getApfDrop8023Frames(@NonNull Context context) {
         return context.getResources().getBoolean(R.bool.config_apfDrop802_3Frames);
     }
 
     /**
      * @return An array of blacklisted EtherType, packets with EtherTypes within it will be dropped.
      */
-    public static int[] getApfEthTypeBlackList(Context context) {
+    public static @NonNull int[] getApfEthTypeBlackList(@NonNull Context context) {
         return context.getResources().getIntArray(R.array.config_apfEthTypeBlackList);
     }
 }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 733b8a0..52fcd4a 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -2174,7 +2174,7 @@
             if (VDBG) log("identical MTU - not setting");
             return;
         }
-        if (LinkProperties.isValidMtu(mtu, newLp.hasGlobalIPv6Address()) == false) {
+        if (!LinkProperties.isValidMtu(mtu, newLp.hasGlobalIpv6Address())) {
             if (mtu != 0) loge("Unexpected mtu value: " + mtu + ", " + iface);
             return;
         }
diff --git a/services/core/java/com/android/server/connectivity/Nat464Xlat.java b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
index 2646d76..262ba7a 100644
--- a/services/core/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
@@ -107,8 +107,8 @@
         // Only run clat on networks that have a global IPv6 address and don't have a native IPv4
         // address.
         LinkProperties lp = nai.linkProperties;
-        final boolean isIpv6OnlyNetwork = (lp != null) && lp.hasGlobalIPv6Address()
-                && !lp.hasIPv4Address();
+        final boolean isIpv6OnlyNetwork = (lp != null) && lp.hasGlobalIpv6Address()
+                && !lp.hasIpv4Address();
 
         // If the network tells us it doesn't use clat, respect that.
         final boolean skip464xlat = (nai.netMisc() != null) && nai.netMisc().skip464xlat;
diff --git a/services/core/java/com/android/server/connectivity/NetworkDiagnostics.java b/services/core/java/com/android/server/connectivity/NetworkDiagnostics.java
index c471f0c..948c690 100644
--- a/services/core/java/com/android/server/connectivity/NetworkDiagnostics.java
+++ b/services/core/java/com/android/server/connectivity/NetworkDiagnostics.java
@@ -34,10 +34,12 @@
 
 import com.android.internal.util.IndentingPrintWriter;
 
+import libcore.io.IoUtils;
+
 import java.io.Closeable;
 import java.io.FileDescriptor;
-import java.io.InterruptedIOException;
 import java.io.IOException;
+import java.io.InterruptedIOException;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -48,17 +50,13 @@
 import java.net.UnknownHostException;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
-import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
-
-import libcore.io.IoUtils;
-
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 /**
  * NetworkDiagnostics
@@ -186,7 +184,7 @@
         // TODO: we could use mLinkProperties.isReachable(TEST_DNS6) here, because we won't set any
         // DNS servers for which isReachable() is false, but since this is diagnostic code, be extra
         // careful.
-        if (mLinkProperties.hasGlobalIPv6Address() || mLinkProperties.hasIPv6DefaultRoute()) {
+        if (mLinkProperties.hasGlobalIpv6Address() || mLinkProperties.hasIpv6DefaultRoute()) {
             mLinkProperties.addDnsServer(TEST_DNS6);
         }
 
diff --git a/tests/net/java/android/net/LinkAddressTest.java b/tests/net/java/android/net/LinkAddressTest.java
index be7bd1b..d462441 100644
--- a/tests/net/java/android/net/LinkAddressTest.java
+++ b/tests/net/java/android/net/LinkAddressTest.java
@@ -81,14 +81,14 @@
         assertEquals(25, address.getPrefixLength());
         assertEquals(0, address.getFlags());
         assertEquals(RT_SCOPE_UNIVERSE, address.getScope());
-        assertTrue(address.isIPv4());
+        assertTrue(address.isIpv4());
 
         address = new LinkAddress(V6_ADDRESS, 127);
         assertEquals(V6_ADDRESS, address.getAddress());
         assertEquals(127, address.getPrefixLength());
         assertEquals(0, address.getFlags());
         assertEquals(RT_SCOPE_UNIVERSE, address.getScope());
-        assertTrue(address.isIPv6());
+        assertTrue(address.isIpv6());
 
         // Nonsensical flags/scopes or combinations thereof are acceptable.
         address = new LinkAddress(V6 + "/64", IFA_F_DEPRECATED | IFA_F_PERMANENT, RT_SCOPE_LINK);
@@ -96,14 +96,14 @@
         assertEquals(64, address.getPrefixLength());
         assertEquals(IFA_F_DEPRECATED | IFA_F_PERMANENT, address.getFlags());
         assertEquals(RT_SCOPE_LINK, address.getScope());
-        assertTrue(address.isIPv6());
+        assertTrue(address.isIpv6());
 
         address = new LinkAddress(V4 + "/23", 123, 456);
         assertEquals(V4_ADDRESS, address.getAddress());
         assertEquals(23, address.getPrefixLength());
         assertEquals(123, address.getFlags());
         assertEquals(456, address.getScope());
-        assertTrue(address.isIPv4());
+        assertTrue(address.isIpv4());
 
         // InterfaceAddress doesn't have a constructor. Fetch some from an interface.
         List<InterfaceAddress> addrs = NetworkInterface.getByName("lo").getInterfaceAddresses();
diff --git a/tests/net/java/android/net/LinkPropertiesTest.java b/tests/net/java/android/net/LinkPropertiesTest.java
index 9a7d487..4177291 100644
--- a/tests/net/java/android/net/LinkPropertiesTest.java
+++ b/tests/net/java/android/net/LinkPropertiesTest.java
@@ -405,8 +405,8 @@
         LinkProperties lp = new LinkProperties();
 
         // No addresses.
-        assertFalse(lp.hasIPv4Address());
-        assertFalse(lp.hasGlobalIPv6Address());
+        assertFalse(lp.hasIpv4Address());
+        assertFalse(lp.hasGlobalIpv6Address());
 
         // Addresses on stacked links don't count.
         LinkProperties stacked = new LinkProperties();
@@ -414,53 +414,53 @@
         lp.addStackedLink(stacked);
         stacked.addLinkAddress(LINKADDRV4);
         stacked.addLinkAddress(LINKADDRV6);
-        assertTrue(stacked.hasIPv4Address());
-        assertTrue(stacked.hasGlobalIPv6Address());
-        assertFalse(lp.hasIPv4Address());
-        assertFalse(lp.hasGlobalIPv6Address());
+        assertTrue(stacked.hasIpv4Address());
+        assertTrue(stacked.hasGlobalIpv6Address());
+        assertFalse(lp.hasIpv4Address());
+        assertFalse(lp.hasGlobalIpv6Address());
         lp.removeStackedLink("stacked");
-        assertFalse(lp.hasIPv4Address());
-        assertFalse(lp.hasGlobalIPv6Address());
+        assertFalse(lp.hasIpv4Address());
+        assertFalse(lp.hasGlobalIpv6Address());
 
         // Addresses on the base link.
-        // Check the return values of hasIPvXAddress and ensure the add/remove methods return true
+        // Check the return values of hasIpvXAddress and ensure the add/remove methods return true
         // iff something changes.
         assertEquals(0, lp.getLinkAddresses().size());
         assertTrue(lp.addLinkAddress(LINKADDRV6));
         assertEquals(1, lp.getLinkAddresses().size());
-        assertFalse(lp.hasIPv4Address());
-        assertTrue(lp.hasGlobalIPv6Address());
+        assertFalse(lp.hasIpv4Address());
+        assertTrue(lp.hasGlobalIpv6Address());
 
         assertTrue(lp.removeLinkAddress(LINKADDRV6));
         assertEquals(0, lp.getLinkAddresses().size());
 
         assertTrue(lp.addLinkAddress(LINKADDRV6LINKLOCAL));
         assertEquals(1, lp.getLinkAddresses().size());
-        assertFalse(lp.hasGlobalIPv6Address());
+        assertFalse(lp.hasGlobalIpv6Address());
 
         assertTrue(lp.addLinkAddress(LINKADDRV4));
         assertEquals(2, lp.getLinkAddresses().size());
-        assertTrue(lp.hasIPv4Address());
-        assertFalse(lp.hasGlobalIPv6Address());
+        assertTrue(lp.hasIpv4Address());
+        assertFalse(lp.hasGlobalIpv6Address());
 
         assertTrue(lp.addLinkAddress(LINKADDRV6));
         assertEquals(3, lp.getLinkAddresses().size());
-        assertTrue(lp.hasIPv4Address());
-        assertTrue(lp.hasGlobalIPv6Address());
+        assertTrue(lp.hasIpv4Address());
+        assertTrue(lp.hasGlobalIpv6Address());
 
         assertTrue(lp.removeLinkAddress(LINKADDRV6LINKLOCAL));
         assertEquals(2, lp.getLinkAddresses().size());
-        assertTrue(lp.hasIPv4Address());
-        assertTrue(lp.hasGlobalIPv6Address());
+        assertTrue(lp.hasIpv4Address());
+        assertTrue(lp.hasGlobalIpv6Address());
 
         // Adding an address twice has no effect.
         // Removing an address that's not present has no effect.
         assertFalse(lp.addLinkAddress(LINKADDRV4));
         assertEquals(2, lp.getLinkAddresses().size());
-        assertTrue(lp.hasIPv4Address());
+        assertTrue(lp.hasIpv4Address());
         assertTrue(lp.removeLinkAddress(LINKADDRV4));
         assertEquals(1, lp.getLinkAddresses().size());
-        assertFalse(lp.hasIPv4Address());
+        assertFalse(lp.hasIpv4Address());
         assertFalse(lp.removeLinkAddress(LINKADDRV4));
         assertEquals(1, lp.getLinkAddresses().size());
 
@@ -546,8 +546,8 @@
         assertFalse("v4only:addr+dns", lp4.isProvisioned());
         lp4.addRoute(new RouteInfo(GATEWAY1));
         assertTrue("v4only:addr+dns+route", lp4.isProvisioned());
-        assertTrue("v4only:addr+dns+route", lp4.isIPv4Provisioned());
-        assertFalse("v4only:addr+dns+route", lp4.isIPv6Provisioned());
+        assertTrue("v4only:addr+dns+route", lp4.isIpv4Provisioned());
+        assertFalse("v4only:addr+dns+route", lp4.isIpv6Provisioned());
 
         LinkProperties lp6 = new LinkProperties();
         assertFalse("v6only:empty", lp6.isProvisioned());
@@ -558,11 +558,11 @@
         lp6.addRoute(new RouteInfo(GATEWAY61));
         assertFalse("v6only:fe80+dns+route", lp6.isProvisioned());
         lp6.addLinkAddress(LINKADDRV6);
-        assertTrue("v6only:fe80+global+dns+route", lp6.isIPv6Provisioned());
+        assertTrue("v6only:fe80+global+dns+route", lp6.isIpv6Provisioned());
         assertTrue("v6only:fe80+global+dns+route", lp6.isProvisioned());
         lp6.removeLinkAddress(LINKADDRV6LINKLOCAL);
-        assertFalse("v6only:global+dns+route", lp6.isIPv4Provisioned());
-        assertTrue("v6only:global+dns+route", lp6.isIPv6Provisioned());
+        assertFalse("v6only:global+dns+route", lp6.isIpv4Provisioned());
+        assertTrue("v6only:global+dns+route", lp6.isIpv6Provisioned());
         assertTrue("v6only:global+dns+route", lp6.isProvisioned());
 
         LinkProperties lp46 = new LinkProperties();
@@ -572,12 +572,12 @@
         lp46.addDnsServer(DNS6);
         assertFalse("dualstack:missing-routes", lp46.isProvisioned());
         lp46.addRoute(new RouteInfo(GATEWAY1));
-        assertTrue("dualstack:v4-provisioned", lp46.isIPv4Provisioned());
-        assertFalse("dualstack:v4-provisioned", lp46.isIPv6Provisioned());
+        assertTrue("dualstack:v4-provisioned", lp46.isIpv4Provisioned());
+        assertFalse("dualstack:v4-provisioned", lp46.isIpv6Provisioned());
         assertTrue("dualstack:v4-provisioned", lp46.isProvisioned());
         lp46.addRoute(new RouteInfo(GATEWAY61));
-        assertTrue("dualstack:both-provisioned", lp46.isIPv4Provisioned());
-        assertTrue("dualstack:both-provisioned", lp46.isIPv6Provisioned());
+        assertTrue("dualstack:both-provisioned", lp46.isIpv4Provisioned());
+        assertTrue("dualstack:both-provisioned", lp46.isIpv6Provisioned());
         assertTrue("dualstack:both-provisioned", lp46.isProvisioned());
 
         // A link with an IPv6 address and default route, but IPv4 DNS server.
@@ -585,8 +585,8 @@
         mixed.addLinkAddress(LINKADDRV6);
         mixed.addDnsServer(DNS1);
         mixed.addRoute(new RouteInfo(GATEWAY61));
-        assertFalse("mixed:addr6+route6+dns4", mixed.isIPv4Provisioned());
-        assertFalse("mixed:addr6+route6+dns4", mixed.isIPv6Provisioned());
+        assertFalse("mixed:addr6+route6+dns4", mixed.isIpv4Provisioned());
+        assertFalse("mixed:addr6+route6+dns4", mixed.isIpv6Provisioned());
         assertFalse("mixed:addr6+route6+dns4", mixed.isProvisioned());
     }
 
@@ -617,16 +617,16 @@
         v6lp.addLinkAddress(LINKADDRV6);
         v6lp.addRoute(new RouteInfo(GATEWAY61));
         v6lp.addDnsServer(DNS6);
-        assertFalse(v6lp.isIPv4Provisioned());
-        assertTrue(v6lp.isIPv6Provisioned());
+        assertFalse(v6lp.isIpv4Provisioned());
+        assertTrue(v6lp.isIpv6Provisioned());
         assertTrue(v6lp.isProvisioned());
 
         LinkProperties v46lp = new LinkProperties(v6lp);
         v46lp.addLinkAddress(LINKADDRV4);
         v46lp.addRoute(new RouteInfo(GATEWAY1));
         v46lp.addDnsServer(DNS1);
-        assertTrue(v46lp.isIPv4Provisioned());
-        assertTrue(v46lp.isIPv6Provisioned());
+        assertTrue(v46lp.isIpv4Provisioned());
+        assertTrue(v46lp.isIpv6Provisioned());
         assertTrue(v46lp.isProvisioned());
 
         assertEquals(ProvisioningChange.STILL_PROVISIONED,