Problem z Serwerem [Java]

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class Server extends Thread {
private ServerSocket serverSocket;
private List<client> clientList;

public Server(int port) throws IOException {
    serverSocket = new ServerSocket(port); 
    clientList = new ArrayList<>(); 
}
@Override
public void run() {
    while(true) {
        try {
            Socket clientSocket = serverSocket.accept(); 
            int id = clientList.size(); 
            Client newClient = new Client(id, clientSocket); 
            clientList.add(newClient); 
            newClient.start(); 
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
}

private List<client> clientList;

Error:(7, 41) java: package com.sun.tools.corba.se.idl.toJavaPortable is not visible
  (package com.sun.tools.corba.se.idl.toJavaPortable is declared in module java.corba, which is not in the module graph)
Error:(7, 1) java: static import only from classes and interfaces
Error:(11, 18) java: cannot find symbol
  symbol:   class Client
  location: class Server
Error:(15, 36) java: cannot find symbol
  symbol:   class Client
  location: class Server
Error:(23, 17) java: cannot find symbol
  symbol:   class Client
  location: class Server
Error:(23, 40) java: cannot find symbol
  symbol:   class Client
  location: class Server