Add @Nullable annotation to the parameter of Object.equals() methods.

Those annotations could be inferred by some tools (like Kotlin), but the
https://checkerframework.org/ doesn't check inherited annotations
complaining about all equals() invocations that get nullable argument.

The change was generated by running

find . -name \*.java | xargs sed -i 's/public boolean equals(Object /public boolean equals(@Nullable Object /'

in the frameworks/base directory and by automatically adding and
formatting required imports if needed. No manual edits.

Bug: 170883422
Test: Annotation change only. Should have not impact.
Exempt-From-Owner-Approval: Mechanical change not specific to any component.
Change-Id: I5eedb571c9d78862115dfdc5dae1cf2a35343580

core/java/android/net/CaptivePortalData.java

@@ -254,7 +254,7 @@ public final class CaptivePortalData implements Parcelable {
     }
 
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof CaptivePortalData)) return false;
         final CaptivePortalData other = (CaptivePortalData) obj;
         return mRefreshTimeMillis == other.mRefreshTimeMillis

core/java/android/net/IpConfiguration.java

@@ -166,7 +166,7 @@ public final class IpConfiguration implements Parcelable {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (o == this) {
             return true;
         }

core/java/android/net/IpPrefix.java

@@ -18,6 +18,7 @@ package android.net;
 
 import android.annotation.IntRange;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.os.Parcel;
@@ -127,7 +128,7 @@ public final class IpPrefix implements Parcelable {
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof IpPrefix)) {
             return false;
         }

core/java/android/net/LinkAddress.java

@@ -357,7 +357,7 @@ public class LinkAddress implements Parcelable {
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof LinkAddress)) {
             return false;
         }

core/java/android/net/LinkProperties.java

@@ -1639,7 +1639,7 @@ public final class LinkProperties implements Parcelable {
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) return true;
 
         if (!(obj instanceof LinkProperties)) return false;

core/java/android/net/MacAddress.java

@@ -160,7 +160,7 @@ public final class MacAddress implements Parcelable {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         return (o instanceof MacAddress) && ((MacAddress) o).mAddr == mAddr;
     }
 

core/java/android/net/Network.java

@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.compat.annotation.UnsupportedAppUsage;
@@ -500,7 +501,7 @@ public class Network implements Parcelable {
     };
 
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof Network)) return false;
         Network other = (Network)obj;
         return this.netId == other.netId;

core/java/android/net/NetworkRequest.java

@@ -553,7 +553,7 @@ public class NetworkRequest implements Parcelable {
         proto.end(token);
     }
 
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (obj instanceof NetworkRequest == false) return false;
         NetworkRequest that = (NetworkRequest)obj;
         return (that.legacyType == this.legacyType &&

core/java/android/net/ProxyInfo.java

@@ -275,7 +275,7 @@ public class ProxyInfo implements Parcelable {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (!(o instanceof ProxyInfo)) return false;
         ProxyInfo p = (ProxyInfo)o;
         // If PAC URL is present in either then they must be equal.

core/java/android/net/RouteInfo.java

@@ -539,7 +539,7 @@ public final class RouteInfo implements Parcelable {
      * Compares this RouteInfo object against the specified object and indicates if they are equal.
      * @return {@code true} if the objects are equal, {@code false} otherwise.
      */
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) return true;
 
         if (!(obj instanceof RouteInfo)) return false;
@@ -575,7 +575,7 @@ public final class RouteInfo implements Parcelable {
         }
 
         @Override
-        public boolean equals(Object o) {
+        public boolean equals(@Nullable Object o) {
             if (!(o instanceof RouteKey)) {
                 return false;
             }

core/java/android/net/UidRange.java

@@ -18,6 +18,7 @@ package android.net;
 
 import static android.os.UserHandle.PER_USER_RANGE;
 
+import android.annotation.Nullable;
 import android.os.Parcel;
 import android.os.Parcelable;
 
@@ -81,7 +82,7 @@ public final class UidRange implements Parcelable {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (this == o) {
             return true;
         }