ExampleJavaList/src/com/company/Client.java

package com.company;

import java.io.*;
import java.net.Socket;

public class Client extends Thread {
    private Socket socket;
    private InputStream is;
    private OutputStream os;

    /**
     *
     * @param socket сокет клиента
     */
    public Client(Socket socket) throws IOException {
        this.socket = socket;
        this.is = this.socket.getInputStream();
        this.os = this.socket.getOutputStream();
    }

    @Override
    public void run() {
        while (!isInterrupted()) {
            try {
                ObjectInputStream objectInputStream = new ObjectInputStream(is);

                UserMessage userMessage = (UserMessage)objectInputStream.readObject();
                switch (userMessage.TYPE) {
                    case DEPOSIT:
                        Bank.deposit(userMessage.BALANCE, userMessage.BILL_NUMBER);
                        break;
                    case WITHDRAW:
                        Bank.withdraw(userMessage.BALANCE, userMessage.BILL_NUMBER);
                        break;
                    case SIGN_CONTRACT:
                        Bank.insert(userMessage.PASSPORT, userMessage.PHONE, userMessage.FULLNAME, userMessage.BALANCE);
                        break;
                    case BREAK_CONTRACT:
                        Bank.delete(userMessage.BILL_NUMBER);
                        break;
                }

            } catch (ClassNotFoundException | IOException exception) {
                System.out.println(exception.getMessage());
                interrupt();
            }
        }

        try {
            is.close();
            os.close();
            socket.close();
        } catch (IOException exception) {
            System.out.println(exception.getMessage());
        }
    }
}