8274227: Remove "impl.prefix" jdk system property usage from InetAddress

Reviewed-by: alanb, dfuchs

src/java.base/share/classes/java/net/Inet4AddressImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2021, 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
@@ -30,7 +30,7 @@
  *
  * @since 1.4
  */
-class Inet4AddressImpl implements InetAddressImpl {
+final class Inet4AddressImpl implements InetAddressImpl {
     public native String getLocalHostName() throws UnknownHostException;
     public native InetAddress[]
         lookupAllHostAddr(String hostname) throws UnknownHostException;

src/java.base/share/classes/java/net/Inet6AddressImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2021, 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
@@ -44,7 +44,7 @@
  *
  * @since 1.4
  */
-class Inet6AddressImpl implements InetAddressImpl {
+final class Inet6AddressImpl implements InetAddressImpl {
 
     public native String getLocalHostName() throws UnknownHostException;
 

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

@@ -1668,51 +1668,6 @@ static InetAddress anyLocalAddress() {
         return impl.anyLocalAddress();
     }
 
-    /*
-     * Load and instantiate an underlying impl class
-     */
-    static InetAddressImpl loadImpl(String implName) {
-        Object impl = null;
-
-        /*
-         * Property "impl.prefix" will be prepended to the classname
-         * of the implementation object we instantiate, to which we
-         * delegate the real work (like native methods).  This
-         * property can vary across implementations of the java.
-         * classes.  The default is an empty String "".
-         */
-        String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
-        try {
-            @SuppressWarnings("deprecation")
-            Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
-            impl = tmp;
-        } catch (ClassNotFoundException e) {
-            System.err.println("Class not found: java.net." + prefix +
-                               implName + ":\ncheck impl.prefix property " +
-                               "in your properties file.");
-        } catch (InstantiationException e) {
-            System.err.println("Could not instantiate: java.net." + prefix +
-                               implName + ":\ncheck impl.prefix property " +
-                               "in your properties file.");
-        } catch (IllegalAccessException e) {
-            System.err.println("Cannot access class: java.net." + prefix +
-                               implName + ":\ncheck impl.prefix property " +
-                               "in your properties file.");
-        }
-
-        if (impl == null) {
-            try {
-                @SuppressWarnings("deprecation")
-                Object tmp = Class.forName(implName).newInstance();
-                impl = tmp;
-            } catch (Exception e) {
-                throw new Error("System property impl.prefix incorrect");
-            }
-        }
-
-        return (InetAddressImpl) impl;
-    }
-
     /**
      * Initializes an empty InetAddress.
      */
@@ -1793,8 +1748,8 @@ private void writeObject (ObjectOutputStream s) throws
 class InetAddressImplFactory {
 
     static InetAddressImpl create() {
-        return InetAddress.loadImpl(isIPv6Supported() ?
-                                    "Inet6AddressImpl" : "Inet4AddressImpl");
+        return isIPv6Supported() ?
+                new Inet6AddressImpl() : new Inet4AddressImpl();
     }
 
     static native boolean isIPv6Supported();

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2005, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2021, 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
@@ -34,7 +34,7 @@
  *
  * @since 1.4
  */
-interface InetAddressImpl {
+sealed interface InetAddressImpl permits Inet4AddressImpl, Inet6AddressImpl {
 
     String getLocalHostName() throws UnknownHostException;
     InetAddress[]