Java.io.StreamCorruptedException: invalid stream header: 75720002

Question

I create a server-client application in which the server sends a PDF file to all connected clients. The problem is that I get this error, and I was looking for a solution, but could not. This is mistake

java.io.StreamCorruptedException: invalid stream header: 75720002 at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:782) at java.io.ObjectInputStream.<init>(ObjectInputStream.java:279) at StudentThread.run(StudentThread.java:102) 

Here is the server send code:

 public void run() { try { String modifiedSentence; in = new BufferedReader(new InputStreamReader(this.socket.getInputStream())); inFromServer = new BufferedReader(new InputStreamReader(System.in)); out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(this.socket.getOutputStream())), true); //String sentence; System.out.println("TeachID. "+id); modifiedSentence = in.readLine(); System.out.println("Student "+id+" says:"+modifiedSentence); arrS=modifiedSentence.split(" "); out.println("Hello "+arrS[2]+","+id); studName=arrS[2]; ((DefaultListModel) Teacher.made_list.getModel()).addElement(studName); while( true ) { modifiedSentence = in.readLine(); arrS=modifiedSentence.split(" "); if(arrS[0].equals("AcceptFile")) { try { ObjectInputStream ois = new ObjectInputStream(socket.getInputStream()); byte[] buffer = (byte[])ois.readObject(); String pic="copyServer"+id+".pdf"; System.out.println(pic); FileOutputStream fos = new FileOutputStream(pic); fos.write(buffer); fos.flush(); fos.close(); } catch(Exception e) { System.out.println("Exception writing"); } } } catch (IOException e) { } finally { try { socket.close(); } catch(IOException e) { } } } public void sendF(String fn,Teacher teach) { try{ out.println("AcceptFile,"); ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream()) ; FileInputStream fis = new FileInputStream(fn); byte[] buffer = new byte[fis.available()]; fis.read(buffer); //ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream()) ; oos.writeObject(buffer); oos.flush(); fis.close(); } catch(Exception e){ e.printStackTrace(); } } public void sendThread(String elem, Teacher teach) { out.println(elem); //System.out.println ("Thread id is " + this.id); System.out.println(this.socket.getInetAddress()); } 

Here is the client receiving the code:

 public void run() { try { out=new PrintWriter(socket.getOutputStream(), true); out.println("Hello Server "+name+","); String modifiedSentence; BufferedReader inFromServer = new BufferedReader( new InputStreamReader( socket.getInputStream() ) ); modifiedSentence = inFromServer.readLine(); System.out.println( modifiedSentence ); arrT=modifiedSentence.split(","); if(arrT[0].equals("Hello "+name)) { studId=Integer.parseInt(arrT[2]); System.out.println("My Id="+studId); } while( true ) { modifiedSentence = inFromServer.readLine(); System.out.println( modifiedSentence ); arrT=modifiedSentence.split(","); if(arrT[0].equals("AcceptFile")) { ObjectInputStream ois = new ObjectInputStream(socket.getInputStream()); byte[] buffer = (byte[])ois.readObject(); String pic="copyServer"+studId+".gif"; System.out.println(pic); FileOutputStream fos = new FileOutputStream(pic); fos.write(buffer); fos.flush(); fos.close(); } } } catch( Exception e ) { e.printStackTrace(); } 

}

Answer 1

BufferedReader can buffer more data from the socket than you have read. Thus, on the client side, the header of your byte[] probably already been read and buffered by your inFromServer reader and will not be available to your ObjectInputStream .

Do not do this. Either do all your marshaling “manually” (using the PrintWriter / BufferedReader pair), or do it all with serializing an object using ObjectOutputStream / ObjectInputStream .