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POObjectOutputStream over a TCP Socket
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  1. POObjectOutputStream over a TCP Socket
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    copied!<p>I wrote a peer-to-peer networked game in Java using the java.net package and for some reason the Socket between the client and the server closes or gets corrupted. I am calling this "peer-to-peer" because one of the clients also runs a server class, which is just a custom class I wrote that accepts Socket connections - one from the other computer and one from the client computer. The connection is being used to move objects back and forth using ObjectOutputStream and ObjectInputStream.</p> <p>The Socket error happens irregularly. The connection is usually open for 5-10 minutes before there is a problem. Sometimes it closes when a new game is started, other times it closes while a game is in progress.</p> <ol> <li>Should I be using keepAlive to keep the connection open?</li> <li>Does anyone have a suggestion on how I should go about troubleshooting this problem?</li> </ol> <p>Here is the code generating the error:</p> <pre><code>/** * Continually checks for messages to be read in. Then it * sends the messages to processMessage if a message is available. */ public void listenForMessages() { int availableBytes; Object obj = null; try { availableBytes = socketStream.available(); if (availableBytes &gt;5) { obj = in.readObject(); message = (ClientMessage) (obj); processMessage(); } } catch(java.io.StreamCorruptedException utoh) { System.out.println("Read failed: " + utoh); try { System.out.println("Number of Bytes available: " + socketStream.available()); utoh.printStackTrace(); System.out.println("Attempting to close socked."); socketStream.close(); } catch(IOException ioe) { System.out.println("Unable to close: " + ioe.toString()); } } catch(IOException e) { System.out.println("Read failed" + e); } </code></pre> <p>Here is the error message and stack trace:</p> <pre><code>Read failed: java.io.StreamCorruptedException: invalid type code: 00 Number of Bytes available: 100 </code></pre> <p>There are two sockets (two streams) active, one for each client. When the other socket throws the same error, I am seeing invalid type code: FF</p> <p><strong>Stack Trace</strong></p> <pre><code>java.io.StreamCorruptedException: invalid type code: 00 at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1355) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) at thornworks.quiz.PlayerInterface.listenForMessages(PlayerInterface.java:227) at thornworks.quiz.PlayerInterface.actionPerformed(PlayerInterface.java:214) at javax.swing.Timer.fireActionPerformed(Timer.java:291) at javax.swing.Timer$DoPostEvent.run(Timer.java:221) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641) at java.awt.EventQueue.access$000(EventQueue.java:84) at java.awt.EventQueue$1.run(EventQueue.java:602) at java.awt.EventQueue$1.run(EventQueue.java:600) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87) at java.awt.EventQueue.dispatchEvent(EventQueue.java:611) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122) </code></pre>
 

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