Sold Java - Creating a File Transfer Service based on UDP

In the first place, this is a school assignment.

The idea is to create some sort of UDP Client/Server application that allows to transfer files in both ways, upload or download. The basic requisites are:

- Connection control.
- Identify the file(s) to transfer, download or upload, with local name and optionally with a remote name.
- Make sure the segments are ordered. If the segments arrive unordered, it should be possible to put them in order.
- Needs to have integrity check (checksum or other), confirmation mechanism (ACK) and needs to allow retransmission in case of lost/error packets.
- Stop-and-Wait algorithm can't be used.

The image we are given as guidance is this:
https://gyazo.com/866c43a2e5c8cf095c8dda5e4284a099

We were also advised to not create a Client/Server generic application, since the files should be able to be transfered both ways. I think that the idea is to create a class wich represents AgentUDP that handles the sending and receiving of the UDP Datagrams and in wich all the communication is defined and then a class TransferCC that implements all the necessary funcionalities for the transfer to happen sucessfully. In the end there should be a simple command line app that allows for GET and PUT commands.

Besides the code, i'm expecting any questions i may have about it to be answered by you. Need this done asap. Hit me up.
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