8319417: (dc) DatagramChannel.connect undocumented behavior

Reviewed-by: alanb

src/java.base/share/classes/java/nio/channels/DatagramChannel.java

@@ -645,6 +645,13 @@ public abstract class DatagramChannel
     /**
      * {@inheritDoc}
      * <p>
+     * If the channel's socket was initially bound to the wildcard address and
+     * is now {@link #isConnected connected}, then the address returned
+     * may be the local address selected as the source address for
+     * datagrams sent via this channel instead of the wildcard address.
+     * When {@link #disconnect} is called, the bound address reverts
+     * to the wildcard address.
+     * <p>
      * If there is a security manager set, its {@code checkConnect} method is
      * called with the local address and {@code -1} as its arguments to see
      * if the operation is allowed. If the operation is not allowed,