ADDITIONAL SYSTEM INFORMATION :
WSL2 Ubuntu 20.04 in Windows 10

A DESCRIPTION OF THE PROBLEM :
ServerSocket in wsl2 java runtime starts also when port is already in use

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
ServerSocket socket1 = new ServerSocket(63132);
ServerSocket socket2 = new ServerSocket(63132);

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
socket2 init fails
ACTUAL -
socket2 inits

---------- BEGIN SOURCE ----------
import java.net.ServerSocket;

class Scratch {
    public static void main(String[] args) {
        ServerSocket socket1 = new ServerSocket(63132);
        ServerSocket socket2 = new ServerSocket(63132);
    }
}

---------- END SOURCE ----------