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

Socket input stream keeps closing or EOF Exception

ServerSocket serverSocket = new ServerSocket(1234);
        Socket socket = serverSocket.accept();
       try {

           System.out.println("Client connected.");

           ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
           ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());
           while(true){
               RequestObject receivedObject = (RequestObject) inputStream.readObject();
               if (receivedObject.type == 1) {
                   applicationPublicKey = receivedObject.publicKey;
                   RequestObject responseObject = new RequestObject();
                   responseObject.setPublicKey(myPair.getPublic());
                   outputStream.writeObject(responseObject);
               } else if (receivedObject.type == 2) {
                   String msg = decrypt(receivedObject.getText().getBytes(), myPair.getPrivate());
                   System.out.println("Encrypted msg: " + receivedObject);
                   System.out.println("Decrypted msg: " + msg);
               }
           }
       }catch (Exception e){
            e.printStackTrace();
       }

ServerSocket serverSocket = new ServerSocket(1234);
        Socket socket = serverSocket.accept();
       try {

           System.out.println("Client connected.");

           ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
           ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());
           while(true){
               RequestObject receivedObject = (RequestObject) inputStream.readObject();
               if (receivedObject.type == 1) {
                   applicationPublicKey = receivedObject.publicKey;
                   RequestObject responseObject = new RequestObject();
                   responseObject.setPublicKey(myPair.getPublic());
                   outputStream.writeObject(responseObject);
               } else if (receivedObject.type == 2) {
                   String msg = decrypt(receivedObject.getText().getBytes(), myPair.getPrivate());
                   System.out.println("Encrypted msg: " + receivedObject);
                   System.out.println("Decrypted msg: " + msg);
               }
           }
       }catch (Exception e){
            e.printStackTrace();
       }

This is a chunk of my Server class, i want the input stream to keep listening to the socket if other requests are called. But it keeps giving me error with the stacktrace:

java.io.EOFException
    at java.base/java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:3244)
    at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1708)
    at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:538)
    at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:496)
    at Server.main(Server.java:29)

java.io.EOFException
    at java.base/java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:3244)
    at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1708)
    at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:538)
    at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:496)
    at Server.main(Server.java:29)

Line 29 in server is :

RequestObject receivedObject = (RequestObject) inputStream.readObject();

RequestObject receivedObject = (RequestObject) inputStream.readObject();

19 Replies

JavaBot•2y ago

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dan1st•2y ago

what is the client code?

EdOP•2y ago

 public static void main(String[] args) throws NoSuchAlgorithmException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048); // Key size in bits
        myPair=keyPairGenerator.generateKeyPair();
        PublicKey controllerPublicKey;

        Socket socket;
        ObjectOutputStream outputStream;
        ObjectInputStream inputStream;


        try {
            socket = new Socket("localhost", 1234);
            outputStream = new ObjectOutputStream(socket.getOutputStream());
            inputStream = new ObjectInputStream(socket.getInputStream());
            RequestObject requestObject = new RequestObject();
            requestObject.setType(1);
            requestObject.setPublicKey(myPair.getPublic());
            outputStream.writeObject(requestObject);

            RequestObject response = (RequestObject) inputStream.readObject();
            controllerPublicKey= response.publicKey;

            RequestObject last=new RequestObject();
            last.type=2;
            String msg="Hello";
            String enc= String.valueOf(encrypt(msg,controllerPublicKey));
            last.setText(enc);


            System.out.println("Server public key:"+response.getPublicKey());

            // Close connections
            outputStream.close();
            inputStream.close();
            socket.close();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

 public static void main(String[] args) throws NoSuchAlgorithmException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048); // Key size in bits
        myPair=keyPairGenerator.generateKeyPair();
        PublicKey controllerPublicKey;

        Socket socket;
        ObjectOutputStream outputStream;
        ObjectInputStream inputStream;


        try {
            socket = new Socket("localhost", 1234);
            outputStream = new ObjectOutputStream(socket.getOutputStream());
            inputStream = new ObjectInputStream(socket.getInputStream());
            RequestObject requestObject = new RequestObject();
            requestObject.setType(1);
            requestObject.setPublicKey(myPair.getPublic());
            outputStream.writeObject(requestObject);

            RequestObject response = (RequestObject) inputStream.readObject();
            controllerPublicKey= response.publicKey;

            RequestObject last=new RequestObject();
            last.type=2;
            String msg="Hello";
            String enc= String.valueOf(encrypt(msg,controllerPublicKey));
            last.setText(enc);


            System.out.println("Server public key:"+response.getPublicKey());

            // Close connections
            outputStream.close();
            inputStream.close();
            socket.close();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

i think the issue is mainly from server side because its the one that keeps shutting down

dan1st•2y ago

Also, note that a single malicious client could completely take over your server

EdOP•2y ago

Yeah this is a primitive project for a class in uni just to demonstrate an idea i am going to build but do you know why the server keeps crashing? Or why do i keep reaching end of input

dan1st•2y ago

I think so the client sends two request objects but the server accepts such objects in a loop it would expect infinitely many request objects but the client just stops sending

EdOP•2y ago

it actually always stops after first request is recieved and response is sent 2nd request is never received by server for some reason

Unknown User•2y ago

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EdOP•2y ago

oh you are actually right... Is there a way to just keep server up all time and deal with each request that he gets from as many clients as possible?

Unknown User•2y ago

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EdOP•2y ago

its working now, but after 2 requests it crash with same error How can i listen tho

Unknown User•2y ago

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EdOP•2y ago

can i do this without threads? true while loop, with if serversockt.accept? then loop again until end

Unknown User•2y ago

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EdOP•2y ago

   while(true) {

            try {
                Socket socket = serverSocket.accept();
                try {

                    System.out.println("Client connected.");

                    ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
                    ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());
                    while (true) {
                        System.out.println("HELLO?");
                        RequestObject receivedObject = (RequestObject) inputStream.readObject();
                        if (receivedObject.type == 1) {
                            applicationPublicKey = receivedObject.publicKey;
                            RequestObject responseObject = new RequestObject();
                            responseObject.setPublicKey(myPair.getPublic());
                            outputStream.writeObject(responseObject);
                        } else if (receivedObject.type == 2) {

                            String msg = decrypt(receivedObject.getText(), myPair.getPrivate());
                            System.out.println("Encrypted msg: " + Arrays.toString(receivedObject.getText()));
                            System.out.println("Decrypted msg: " + msg);
                        }

                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }catch (Exception e){
                System.out.println("NO CONNECTION");
            }
        }

   while(true) {

            try {
                Socket socket = serverSocket.accept();
                try {

                    System.out.println("Client connected.");

                    ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
                    ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());
                    while (true) {
                        System.out.println("HELLO?");
                        RequestObject receivedObject = (RequestObject) inputStream.readObject();
                        if (receivedObject.type == 1) {
                            applicationPublicKey = receivedObject.publicKey;
                            RequestObject responseObject = new RequestObject();
                            responseObject.setPublicKey(myPair.getPublic());
                            outputStream.writeObject(responseObject);
                        } else if (receivedObject.type == 2) {

                            String msg = decrypt(receivedObject.getText(), myPair.getPrivate());
                            System.out.println("Encrypted msg: " + Arrays.toString(receivedObject.getText()));
                            System.out.println("Decrypted msg: " + msg);
                        }

                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }catch (Exception e){
                System.out.println("NO CONNECTION");
            }
        }

something like this logically correct? yeah thats probably what i am planning to do

Unknown User•2y ago

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EdOP•2y ago

yeah i fixed it its working now Thanks a lot mate i really appreciate it!

JavaBot•2y ago

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JavaBot•2y ago

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Socket input stream keeps closing or EOF Exception

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