Java ServerSocket不接受来自通过LAN Cable连接的远程客户端的请求

I have created a Server using java.net sockets, I try accessing it via localhost client and it is accepting the requests and responding to client, but when I try accessing it remotely from another computer via LAN cable connection, it doesn't accept any connection even though it is listening to the local port (9999), then to see if the port does not work I configured Apache Web Server to listen to port (9999) and it does work, so I set it to listen to a different port but no luck and tried opening various ports on the firewall still doesn't work.I have created a Server using java.net sockets,