How to determine what is hanging on the port?

Question

ubuntu

I can’t start using port 8080 because something hangs on it, I don’t remember what it can.
sudo netstat -plnt | grep ':8080'

tcp6       0      0 :::8080                 :::*                    LISTEN      1781/java

What could it be?
How to find out more about 1781?

Answer 1

/proc/1781/cmdline