--- old/src/java.base/share/classes/sun/nio/ch/Net.java	2020-01-06 11:04:36.000000000 +0000
+++ new/src/java.base/share/classes/sun/nio/ch/Net.java	2020-01-06 11:04:35.000000000 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2020, 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
@@ -615,50 +615,83 @@
     // -- Multicast support --
 
     /**
-     * Join IPv4 multicast group
+     * Join IPv4 multicast group, optionally source-specific.
+     *
+     * @param fd file descriptor
+     * @param group IPv4 multicast group
+     * @param index index of network interface
+     * @param infAddress IPv4 address that identifies network interface
+     * @param source IPv4 source address or 0
+     * @return 0 or IOS_UNAVAILABLE
      */
-    static int join4(FileDescriptor fd, int group, int interf, int source)
+    static int join4(FileDescriptor fd, int group, int index, int infAddress, int source)
         throws IOException
     {
-        return joinOrDrop4(true, fd, group, interf, source);
+        return joinOrDrop4(true, fd, group, index, infAddress, source);
     }
 
     /**
-     * Drop membership of IPv4 multicast group
+     * Drop membership of IPv4 multicast group, optionally source-specific.
+     *
+     * @param fd file descriptor
+     * @param group IPv4 multicast group
+     * @param index index of network interface
+     * @param infAddress IPv4 address that identifies network interface
+     * @param source IPv4 source address or 0
      */
-    static void drop4(FileDescriptor fd, int group, int interf, int source)
+    static void drop4(FileDescriptor fd, int group, int index, int infAddress, int source)
         throws IOException
     {
-        joinOrDrop4(false, fd, group, interf, source);
+        joinOrDrop4(false, fd, group, index, infAddress, source);
     }
 
-    private static native int joinOrDrop4(boolean join, FileDescriptor fd, int group, int interf, int source)
+    private static native int joinOrDrop4(boolean join, FileDescriptor fd, int group,
+                                          int index, int infAddress, int source)
         throws IOException;
 
     /**
      * Block IPv4 source
+     *
+     * @param fd file descriptor
+     * @param group IPv4 multicast group
+     * @param index index of network interface
+     * @param infAddress IPv4 address that identifies network interface
+     * @param source IPv4 source address
+     * @return 0 or IOS_UNAVAILABLE
      */
-    static int block4(FileDescriptor fd, int group, int interf, int source)
+    static int block4(FileDescriptor fd, int group, int index, int infAddress, int source)
         throws IOException
     {
-        return blockOrUnblock4(true, fd, group, interf, source);
+        return blockOrUnblock4(true, fd, group, index, infAddress, source);
     }
 
     /**
-     * Unblock IPv6 source
+     * Unblock IPv4 source
+     *
+     * @param fd file descriptor
+     * @param group IPv4 multicast group
+     * @param index index of network interface
+     * @param infAddress IPv4 address that identifies network interface
+     * @param source IPv4 source address
      */
-    static void unblock4(FileDescriptor fd, int group, int interf, int source)
+    static void unblock4(FileDescriptor fd, int group, int index, int infAddress, int source)
         throws IOException
     {
-        blockOrUnblock4(false, fd, group, interf, source);
+        blockOrUnblock4(false, fd, group, index, infAddress, source);
     }
 
     private static native int blockOrUnblock4(boolean block, FileDescriptor fd, int group,
-                                              int interf, int source)
+                                              int index, int infAddress, int source)
         throws IOException;
 
     /**
-     * Join IPv6 multicast group
+     * Join IPv6 multicast group, optionally source-specific.
+     *
+     * @param fd file descriptor
+     * @param group IPv6 multicast group address
+     * @param index index of network interface
+     * @param source IPv6 source address or 0
+     * @return 0 or IOS_UNAVAILABLE
      */
     static int join6(FileDescriptor fd, byte[] group, int index, byte[] source)
         throws IOException
@@ -668,6 +701,11 @@
 
     /**
      * Drop membership of IPv6 multicast group
+     *
+     * @param fd file descriptor
+     * @param group IPv6 multicast group address
+     * @param index index of network interface
+     * @param source IPv6 source address or 0
      */
     static void drop6(FileDescriptor fd, byte[] group, int index, byte[] source)
         throws IOException
@@ -675,11 +713,18 @@
         joinOrDrop6(false, fd, group, index, source);
     }
 
-    private static native int joinOrDrop6(boolean join, FileDescriptor fd, byte[] group, int index, byte[] source)
+    private static native int joinOrDrop6(boolean join, FileDescriptor fd, byte[] group,
+                                          int index, byte[] source)
         throws IOException;
 
     /**
      * Block IPv6 source
+     *
+     * @param fd file descriptor
+     * @param group IPv6 multicast group address
+     * @param index index of network interface
+     * @param source IPv6 source address or null
+     * @return 0 or IOS_UNAVAILABLE
      */
     static int block6(FileDescriptor fd, byte[] group, int index, byte[] source)
         throws IOException
@@ -689,6 +734,11 @@
 
     /**
      * Unblock IPv6 source
+     *
+     * @param fd file descriptor
+     * @param group IPv6 multicast group address
+     * @param index index of network interface
+     * @param source IPv6 source address or null
      */
     static void unblock6(FileDescriptor fd, byte[] group, int index, byte[] source)
         throws IOException
@@ -696,10 +746,11 @@
         blockOrUnblock6(false, fd, group, index, source);
     }
 
-    static native int blockOrUnblock6(boolean block, FileDescriptor fd, byte[] group, int index, byte[] source)
+    private static native int blockOrUnblock6(boolean block, FileDescriptor fd, byte[] group,
+                                              int index, byte[] source)
         throws IOException;
 
-    static native void setInterface4(FileDescriptor fd, int interf) throws IOException;
+    static native void setInterface4(FileDescriptor fd, int infAddress) throws IOException;
 
     static native int getInterface4(FileDescriptor fd) throws IOException;