8282917: Remove InetAddressImplFactory from InetAddress

Reviewed-by: dfuchs, jpai

Author: AlekseiEfimov

src/java.base/share/classes/java/net/InetAddress.java

@@ -412,6 +412,9 @@ static boolean ipv6AddressesFirst(int lookupCharacteristics) {
     // Native method to check if IPv4 is available
     private static native boolean isIPv4Available();
 
+    // Native method to check if IPv6 is available
+    private static native boolean isIPv6Supported();
+
     /**
      * The {@code RuntimePermission("inetAddressResolverProvider")} is
      * necessary to subclass and instantiate the {@code InetAddressResolverProvider}
@@ -1270,7 +1273,8 @@ private String extractHostAddr(String hostEntry, String host) {
 
     static {
         // create the impl
-        impl = InetAddressImplFactory.create();
+        impl = isIPv6Supported() ?
+                new Inet6AddressImpl() : new Inet4AddressImpl();
 
         // impl must be initialized before calling this method
         PLATFORM_LOOKUP_POLICY = initializePlatformLookupPolicy();
@@ -1826,16 +1830,3 @@ private void writeObject (ObjectOutputStream s) throws IOException {
         s.writeFields();
     }
 }
-
-/*
- * Simple factory to create the impl
- */
-class InetAddressImplFactory {
-
-    static InetAddressImpl create() {
-        return isIPv6Supported() ?
-                new Inet6AddressImpl() : new Inet4AddressImpl();
-    }
-
-    static native boolean isIPv6Supported();
-}

src/java.base/share/native/libnet/InetAddress.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -76,8 +76,19 @@ Java_java_net_InetAddress_init(JNIEnv *env, jclass cls) {
 /*
  * Class:     java_net_InetAddress
  * Method:    isIPv4Available
+ * Signature: ()Z
  */
 JNIEXPORT jboolean JNICALL
 Java_java_net_InetAddress_isIPv4Available(JNIEnv *env, jclass clazz) {
     return ipv4_available();
 }
+
+/*
+ * Class:     java_net_InetAddress
+ * Method:    isIPv6Supported
+ * Signature: ()Z
+ */
+JNIEXPORT jboolean JNICALL
+Java_java_net_InetAddress_isIPv6Supported(JNIEnv *env, jclass clazz) {
+    return ipv6_available();
+}