How to tell if a socket client has disconnected?

I have a server that has a List with all clients connected.

The client connects and the connection is managed on a unique thread with infinite loop communication.

The problem when I drop the client or close the connection, I do not know how to implement on the server that the client has terminated the connection. I know that the connection is closed by itself, but the client socket object is still saved in List .

In short, I do not know when to call method remove of List .

I have tried to use the isConnected or isClosed method of the socket. It did not work.

UPDATE

I'm doing it this way and it's working.

@Override
public void run() {

    //loop espera mensagem do client
    while(true){
        //aguarda receber uma mensagem
        String response = receive();
        //condição para encerrar comunicação
        if(response==null)
            break;
        //valida mensagem
        Message msg;
        try{
             msg = new Gson().fromJson(response, Message.class);
        }catch(Exception e){
            //mensagem invalida, volta ao inicio do laço e espera nova mensagem.
            continue;
        }            
        //cria thread para tratar mensagem
        new Thread(new Runnable(){
            @Override
            public void run() {
                managerMessage(msg);
            }
        }).start();
    }
    System.out.println("Cliente desconectou");
    //remove socket da lista de conexões abertas
    server.removeConnection(this);

}

The receive () method I created it is waiting for a message from the client, while not receiving a message the method does not complete. I noticed that when I drop the client, receive () starts to return null , so far it's working, I do not know if it's the best way.

public String receive(){
    //espera receber mensagem
    while(receiver.hasNextLine())
        return receiver.nextLine();//quando um mensagem chega retona
    return null;
} 

obs: receiver is Scanner was created as follows new Scanner(socket.getInputStream());