Is UDP (in Java or otherwise) full duplex by default?

Question

I.e. am I able to read from and write to the same socket using two different threads, given that I'm doing all communication in the form of datagrams?

Answer 1

UDP IS in fact fully duplex.

You can have a server listening from as well as writing to the same socket

Answer 2

UDP, in the right circumstances, can be considered fully duplex, but by itself, it is not, whereas TCP, on the other hand, is always fully duplex.

UDP is a fire-and-forget, best-effort protocol, but the upper layers can use it in a fully duplex fashion.

TCP requires handshaking and other two-way communication.