diff -r c619a34cb99b -r 8161f879d704 jdk/src/share/classes/java/net/MulticastSocket.java
--- a/jdk/src/share/classes/java/net/MulticastSocket.java	Tue Dec 01 08:55:15 2009 -0800
+++ b/jdk/src/share/classes/java/net/MulticastSocket.java	Wed Dec 02 12:17:42 2009 +0000
@@ -289,6 +289,7 @@
             throw new SocketException("Socket is closed");
         }
 
+        checkAddress(mcastaddr, "joinGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkMulticast(mcastaddr);
@@ -323,6 +324,7 @@
             throw new SocketException("Socket is closed");
         }
 
+        checkAddress(mcastaddr, "leaveGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkMulticast(mcastaddr);
@@ -370,6 +372,7 @@
         if (oldImpl)
             throw new UnsupportedOperationException();
 
+        checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "joinGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress());
@@ -416,6 +419,7 @@
         if (oldImpl)
             throw new UnsupportedOperationException();
 
+        checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "leaveGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress());
@@ -441,6 +445,7 @@
         if (isClosed()) {
             throw new SocketException("Socket is closed");
         }
+        checkAddress(inf, "setInterface");
         synchronized (infLock) {
             getImpl().setOption(SocketOptions.IP_MULTICAST_IF, inf);
             infAddress = inf;
@@ -632,6 +637,7 @@
         throws IOException {
             if (isClosed())
                 throw new SocketException("Socket is closed");
+            checkAddress(p.getAddress(), "send");
             synchronized(ttlLock) {
                 synchronized(p) {
                     if (connectState == ST_NOT_CONNECTED) {