Convert a byte array to integer in Java and vice versa

I want to store some data into byte arrays in Java. Basically just numbers which can take up to 2 Bytes per number. I'd like to know how I can convert an integer into a 2 byte long byte array and vice versa. I found a lot of solutions googling but most of them don't explain what happens in the code. There's a lot of shifting stuff I don't really understand so I would appreciate a basic explanation

[ledsun]

java でバイト配列から何かに変換するにはByteBufferを使うのが便利。