My own bitcoin miner I am trying to write simple bitcoin miner on Java

How to request miner pool?
What is miner pool protocol?

How to send data to stratum pool? (socket, post request or ect...)
What need send there?

Thank you for help!
The mining protocol between miner and pool is called Stratum.

See https://en.bitcoin.it/wiki/Stratum_mining_protocol

How to open a TCP connection and send/receive data using Java; there should be plenty of resources you can find on that.