Object instantiation failure: only the first is created

Question

I have a class in JAVA which is a Server. I put in this server class the port argument, for example.

If I were to call this class I would do so: new Servidor(5000);.

5000 is the argument of this server class, so I created a new frame class with a button, and in the action of this button I call this server class 5 times, but with the different arguments and stayed like this :

private void botaoIniciaServidoresActionPerformed(java.awt.event.ActionEvent evt) {                                                      

        Servidor servidor = new Servidor(5000);
        Servidor servidor1 = new Servidor(5001);
        Servidor servidor2 = new Servidor(5002);
        Servidor servidor3 = new Servidor(5003);
        Servidor servidor4 = new Servidor(5004);
}

But the problem is that when I click the button, the only server that starts is the first on port 5000, I’ve already debugged here and noticed that only the first instruction is executed, the other 4 are not. Why is that?

I’ve tried it like this:

private void botaoIniciaServidoresActionPerformed(java.awt.event.ActionEvent evt) {                                                      

        new Servidor(5000);
        new Servidor(5001);
        new Servidor(5002);
        new Servidor(5003);
        new Servidor(5004);
}

Even so it doesn’t work, I debug in both cases and only the 5000 port server is started.

---

Updating

The builder of the class Servidor:

public Servidor(int porta) {

    try {
    serverSocket = new ServerSocket(porta);
    System.out.println("Servidor "+ porta + " Online ");

    serverSocket.setSoTimeout(0);

    while (true) {
        socket = serverSocket.accept();

        new Thread(new ListenerSocket(socket)).start();
    }

    } catch (IOException ex) {
    }
}

---

Update 2

I’ll post the code, just to add, I have no problem with the server, it runs perfectly. I only have problem to call 2 or more servers of another frame class with a button, because I want to start here and rotate about 100 servers on different ports, and as it is I need to stay one by one changing the port and starting. Ever imagined? I debugged and Observer that Netbeans only runs one server and others do not.

Follows the code:

package Pacote;

import Pacote.Mensageiro.Acao;
import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

@SuppressWarnings("unchecked")
public class Servidor {

    private ServerSocket serverSocket;
    private Socket socket;
    private Map<String, ObjectOutputStream> mapOnline = new HashMap<String, ObjectOutputStream>();
    public int porta;

    // nova lista para armazenar todas as janelas ativas
    private Map<String, ObjectOutputStream> mapJanelaLista = new HashMap<String, ObjectOutputStream>();
    Calendar data = Calendar.getInstance();
    int horas = data.get(Calendar.HOUR_OF_DAY);
    int minutos = data.get(Calendar.MINUTE);
    int segundos = data.get(Calendar.SECOND);

    public Servidor(int porta) {

        try {
            serverSocket = new ServerSocket(porta);
            System.out.println("Servidor "+ porta + " Online ");

            serverSocket.setSoTimeout(0);

            while (true) {
                socket = serverSocket.accept();

                new Thread(new ListenerSocket(socket)).start();
            }

        } catch (IOException ex) {

        }
    }

    private class ListenerSocket implements Runnable {

        private ObjectOutputStream output;
        private ObjectInputStream input;

        public ListenerSocket(Socket socket) {
            try {
                this.output = new ObjectOutputStream(socket.getOutputStream());
                this.input = new ObjectInputStream(socket.getInputStream());
            } catch (IOException ex) {

            }
        }

        public void run() {
            Mensageiro message = null;
            try {
                while ((message = (Mensageiro) input.readObject()) != null) {
                    Acao action = message.getAcao();

                    if (action.equals(Acao.CONNECT)) {
                        boolean isConnect = conectar(message, output);
                        if (isConnect) {
                            mapOnline.put(message.getNome(), output);
                            enviarOnline();
                            enviarJanelaLista();
                            System.out.println(message.getNome() + " " + new Date().getHours() + ":" + new Date().getMinutes() + " Entrou ");
                        }
                    } else if (action.equals(Acao.DISCONNECT)) {
                        desconectar(message, output);
                        enviarOnline();
                        enviarJanelaLista();

                        return;
                    } else if (action.equals(Acao.SEND_ONE)) {
                        enviarUm(message);
                    } else if (action.equals(Acao.SEND_ALL)) {
                        enviarTodos(message);
                    } else if (action.equals(Acao.DISCONNECT_JANELA_LISTA)) { // faz a conexao para a janela da lista
                        // remove a janela da lista
                        mapJanelaLista.remove(message.getNome());
                        // formamos o fim do while (da thread referente) para esta janela
                        message = null;
                    } else if (action.equals(Acao.CONNECT_JANELA_LISTA)) { // desconecta a janela da lista

                        //adiciona a janela na lista
                        mapJanelaLista.put(message.getNome(), output);
                        enviarJanelaLista();
                    }
                }
            } catch (IOException ex) {
                desconectar(message, output);

            } catch (ClassNotFoundException ex) {
                Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    private boolean conectar(Mensageiro message, ObjectOutputStream output) {

        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            if (kv.getKey().equalsIgnoreCase(message.getNome())) {
                message.setText("NO");
                enviar(message, output);
                return false;
            }

        }

        if (mapOnline.size() == 0) {
            message.setText("YES");
            enviar(message, output);
            return true;
        } else {
            message.setText("YES");
            enviar(message, output);
            return true;
        }

        // return false;
    }

    private void desconectar(Mensageiro message, ObjectOutputStream output) {
        // como temos agora 2 tipos de mensagem, do chat e da janela, precisamos fazer uns testes extras
        if (message != null) {
            // vamos aqui retirar um cliente do chat
            if (mapOnline.containsKey(message.getNome())) {
                mapOnline.remove(message.getNome());
                enviarOnline();
                enviarJanelaLista();
            }

            // vamos aqui retirar um janela de lista
            if (mapJanelaLista.containsKey(message.getNome())) {
                mapJanelaLista.remove(message.getNome());
            }
            System.out.println(message.getNome() + " " + new Date().getHours() + ":" + new Date().getMinutes() + " Saiu ");
        }
    }

    private void enviar(Mensageiro message, ObjectOutputStream output) {
        try {
            output.writeObject(message);
        } catch (IOException ex) {
            Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    private void enviarUm(Mensageiro message) {
        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            if (kv.getKey().equals(message.getNomeReservado())) {
                try {
                    kv.getValue().writeObject(message);
                } catch (IOException ex) {
                    Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
    }

    private void enviarTodos(Mensageiro message) {
        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            if (!kv.getKey().equals(message.getNome())) {
                message.setAcao(Acao.SEND_ONE);
                try {
                    kv.getValue().writeObject(message);
                } catch (IOException ex) {
                    Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
    }

    private void enviarOnline() {
        Set<String> setNames = new HashSet<String>();
        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            setNames.add(kv.getKey());
        }

        Mensageiro message = new Mensageiro();
        message.setAcao(Acao.USERS_ONLINE);
        message.setSetOnline(setNames);

        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            message.setNome(kv.getKey());
            try {
                kv.getValue().writeObject(message);
            } catch (IOException ex) {
                Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    // esse metodo atualiza a lista de clientes ativos no chat para as janelas da lista que estão abertas
    private void enviarJanelaLista() {
        Set<String> setNames = new HashSet<String>();
        for (Map.Entry<String, ObjectOutputStream> kv : mapOnline.entrySet()) {
            setNames.add(kv.getKey());
        }

        Mensageiro message = new Mensageiro();
        message.setAcao(Acao.USERS_ONLINE);
        message.setSetOnline(setNames);

        for (Map.Entry<String, ObjectOutputStream> kv : mapJanelaLista.entrySet()) {
            message.setNome(kv.getKey());
            try {
                kv.getValue().writeObject(message);
            } catch (IOException ex) {
                Logger.getLogger(Servidor.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }



}

Answer 1

Your problem is on this call:

while (true) {
socket = serverSocket.accept();
new Thread(new ListenerSocket(socket)).start();
}

Not only serverSocket.accept() is a synchronous call as there is no output condition for the cycle while. The way it is, the first instantiated server will run without ever leaving.

You can choose to switch to:

socket = serverSocket.accept();
new Thread(new ListenerSocket(socket)).start();

This way, the server will wait for a connection and when it receives it will allow the other servers to be instantiated (in the same way that this, i.e, will wait for the first connection).

Or you can start each server on its own thread.

new Thread(new Servidor(5000));
new Thread(new Servidor(5001));
...