Java Community | Help. Code. Learn.•2mo ago

I've created 1 client server, but everytime I'm exiting the server I can't connect anymore

In order to fix this problem I need to change the port. But the problem is that I did it like 8 times, so 8 ports are broken now.. When I'm writing bye, the server shuts down, but it seems like the port is still taken, what to do and how to fix it? Thank you

53 Replies

JavaBot•2mo ago

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dan1st•2mo ago

Are you actually stopping the server process?

YardenOP•2mo ago

I'm doing this Also something similar in the client

dan1st•2mo ago

Are you also closing the ServerSocket? Can you show the full class in a code block (NOT a screenshot)?

YardenOP•2mo ago

I do socket.close() so I think so no? yes i will send you

YardenOP•2mo ago

It doesn't let me it says it's too long

dan1st•2mo ago

If you don't close serverSocket, the server will still be bound skip the whole client handling code

YardenOP•2mo ago

dan1st•2mo ago

likely still too much text

john•2mo ago

public class Server {

    @SuppressWarnings("resource")
    public static void main(String[] args) throws IOException {
        
        Socket socket = null;
        InputStreamReader inputStreamReader = null;
        OutputStreamWriter outputStreamWriter = null;
        BufferedReader bufferedReader = null;
        BufferedWriter bufferedWriter = null;

        ServerSocket serverSocket = null;
        
        serverSocket = new ServerSocket(1234);
        

        while(true){
            
            try {

                socket = serverSocket.accept();
                
                inputStreamReader = new InputStreamReader(socket.getInputStream());
                outputStreamWriter = new OutputStreamWriter(socket.getOutputStream());
                
                bufferedReader = new BufferedReader(inputStreamReader);
                bufferedWriter = new BufferedWriter(outputStreamWriter);
                
                while(true) {
                    
                    String msgFromClient = bufferedReader.readLine();
                    
                    System.out.println("Client: " + msgFromClient);
                    
                    bufferedWriter.write("MSG Received");
                    bufferedWriter.newLine();
                    bufferedWriter.flush();
                    
                    
                    
                    if (msgFromClient.equalsIgnoreCase("BYE")) {
                        
                        bufferedWriter.flush();
                        socket.shutdownOutput(); 
                        break;
                    }
                }

public class Server {

    @SuppressWarnings("resource")
    public static void main(String[] args) throws IOException {
        
        Socket socket = null;
        InputStreamReader inputStreamReader = null;
        OutputStreamWriter outputStreamWriter = null;
        BufferedReader bufferedReader = null;
        BufferedWriter bufferedWriter = null;

        ServerSocket serverSocket = null;
        
        serverSocket = new ServerSocket(1234);
        

        while(true){
            
            try {

                socket = serverSocket.accept();
                
                inputStreamReader = new InputStreamReader(socket.getInputStream());
                outputStreamWriter = new OutputStreamWriter(socket.getOutputStream());
                
                bufferedReader = new BufferedReader(inputStreamReader);
                bufferedWriter = new BufferedWriter(outputStreamWriter);
                
                while(true) {
                    
                    String msgFromClient = bufferedReader.readLine();
                    
                    System.out.println("Client: " + msgFromClient);
                    
                    bufferedWriter.write("MSG Received");
                    bufferedWriter.newLine();
                    bufferedWriter.flush();
                    
                    
                    
                    if (msgFromClient.equalsIgnoreCase("BYE")) {
                        
                        bufferedWriter.flush();
                        socket.shutdownOutput(); 
                        break;
                    }
                }

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john•2mo ago

socket.close(); inputStreamReader.close(); outputStreamWriter.close(); bufferedReader.close(); bufferedWriter.close(); System.out.println("Socket closed: " + socket.isClosed());

            }catch(IOException e) {
                e.printStackTrace();
            }
        }
    }
}

            }catch(IOException e) {
                e.printStackTrace();
            }
        }
    }
}

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dan1st•2mo ago

Ok so why are you starting more server processes? If a client disconnects, another client can connect

YardenOP•2mo ago

What do you mean? How to avoid this?

dan1st•2mo ago

Stop the server before starting a new one? Why do you want to avoid that? Just don't start more servers?

YardenOP•2mo ago

I want this to be only 1 client server, so when the client disconnects I want the server to disconnects. That's why I want to avoid that The next level, the next program, will be for many clients, but I want to do this step by step

dan1st•2mo ago

so the server should only handle a single client and then stop?

YardenOP•2mo ago

Yep once the client says "bye"

dan1st•2mo ago

you already almost have that then you don't need the loop and also make sure you close serverSocket at the end

YardenOP•2mo ago

The guy in the tutorial said: * The first loop: ensures the server is constantly running. * The second loop: ensures that, once the client is connected, the server is constantly interacting with the client until the client disconnects. Where was he wrong? Maybe I've missed something?

dan1st•2mo ago

I am talking about the outer loop currently, your server is capable of handling multiple clients

YardenOP•2mo ago

fixed it thank youuu! There is only 1 issue: When i'm changing back the port to a port I already used before, I still got the error. Is there a way to "free" the problematic ports?

dan1st•2mo ago

that's exactly what your old version did stop the servers that are still running

dan1st•2mo ago

In the console view in Eclipse, you have these button

dan1st•2mo ago

the red button stops the current program, the double-X clears the stopped consoles so red button to stop the currently running program, then double-X to make it not show stopped programs, then the red button again to stop the currently shown program etc

YardenOP•2mo ago

doesn't work 🫠 The port is still broken

dan1st•2mo ago

Show me the Eclipse console view

YardenOP•2mo ago

dan1st•2mo ago

there's the double-X button as I said

dan1st•2mo ago

you need to click that and then the other button should turn red

YardenOP•2mo ago

I did also I'll show you

YardenOP•2mo ago

And then i'm pressing f11 and i get an error

dan1st•2mo ago

now since the button is red, you can click the red button to stop that process then you click on the double-X again and on the red button again and on the double-X and on the red button until you stopped all servers

YardenOP•2mo ago

You are just a god Thank you so much ❤️

JavaBot•2mo ago

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YardenOP•2mo ago

Last last last issue When I'm trying to write a new line, it shows the marker on the existing server's message, but why? I have the line "newLine() It suppose to take 1 line space no?

YardenOP•2mo ago

Or maybe am I suppose to open a new help post?

dan1st•2mo ago

? Maybe you are using System.out.print instead of System.out.println keep it open as long as you want to and close it if you think you are finished with it

YardenOP•2mo ago

Wait yes totally this So i'm a bit confused, what exactly the use of newLine()? I thought it take a line space

dan1st•2mo ago

What do you mean with newLine()?

YardenOP•2mo ago

dan1st•2mo ago

Is that BufferedWriter going to System.out?

YardenOP•2mo ago

Hmmm probably not? Isn't it "catch" the message the client writes in the system.out? I mean the BufferedReader And then the writer put it in the server's chat

dan1st•2mo ago

How did you create bufferedWriter? and what prints it to the console? Are you using a BufferedReader on the other side?

YardenOP•2mo ago

I have InputStreamReader, the BufferedReader takes the information from the InputStreamReader. The System.out prints in to the console no? I'm using BufferedReader on both client and server sides

dan1st•2mo ago

Can you show where this is received and printed to the console?

YardenOP•2mo ago

client or server? socket = serverSocket.accept();
inputStreamReader = new InputStreamReader(socket.getInputStream()); outputStreamWriter = new OutputStreamWriter(socket.getOutputStream());
bufferedReader = new BufferedReader(inputStreamReader); bufferedWriter = new BufferedWriter(outputStreamWriter);
while(true) {
String msgFromClient = bufferedReader.readLine();
System.out.println("Client: " + msgFromClient);
bufferedWriter.write("MSG Received"); bufferedWriter.newLine(); bufferedWriter.flush();

dan1st•2mo ago

client

john•2mo ago

try {
            socket = new Socket("localhost", 1234); 
            inputStreamReader = new InputStreamReader(socket.getInputStream());
            outputStreamWriter = new OutputStreamWriter(socket.getOutputStream());
            
            bufferedReader = new BufferedReader(inputStreamReader);
            bufferedWriter = new BufferedWriter(outputStreamWriter);
            
            Scanner scanner = new Scanner(System.in);
            
            while(true){
                String msgToSend = scanner.nextLine();
                bufferedWriter.write(msgToSend);
                bufferedWriter.newLine();
                
                System.out.println("Server: " + bufferedReader.readLine());
                
                if(msgToSend.equalsIgnoreCase("BYE"))
                    break;
                    
            }

try {
            socket = new Socket("localhost", 1234); 
            inputStreamReader = new InputStreamReader(socket.getInputStream());
            outputStreamWriter = new OutputStreamWriter(socket.getOutputStream());
            
            bufferedReader = new BufferedReader(inputStreamReader);
            bufferedWriter = new BufferedWriter(outputStreamWriter);
            
            Scanner scanner = new Scanner(System.in);
            
            while(true){
                String msgToSend = scanner.nextLine();
                bufferedWriter.write(msgToSend);
                bufferedWriter.newLine();
                
                System.out.println("Server: " + bufferedReader.readLine());
                
                if(msgToSend.equalsIgnoreCase("BYE"))
                    break;
                    
            }

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dan1st•2mo ago

hm, that's weird

YardenOP•2mo ago

Right? But it seems like everything is working pretyy much alright So thank you very much ❤️

JavaBot•2mo ago

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I've created 1 client server, but everytime I'm exiting the server I can't connect anymore