`java.net.DatagramSocket` has been updated in this release to add support for joining multicast groups. It now defines `joinGroup` and `leaveGroup` methods to join and leave multicast groups. The class level API documentation of `java.net.DatagramSocket` has been updated to explain how a plain `DatagramSocket` can be configured and used to join and leave multicast groups.

This change means that the `DatagramSocket` API can be used for multicast applications without needing to use the legacy `java.net.MulticastSocket` API. The `MulticastSocket` API works as before, although most of its methods are deprecated.

More information on the rationale of this change can be seen in the CSR JDK-8260667.