Question

So I am writing a multithreaded server which takes in as an input the server name, port, number of threads, and a file name to request.. My design is to create a socket through main and then extend a Runnable object (which takes in a socket and the file name).. I also have a timertask which fires when 5 seconds are over and then closes and stops all threads.. My current design is to create the socket in main, pass it to runnable (where there is a while loop on condition x, requesting the file over and over), and then when the task fires up it sets the private shared variable x in runnable to false.

I am facing a lot of broken pipe issues which leads me to believe my design is flawed.. Am I missing something? I am not using synchronized/locked variables. Should I create a new socket for every file request?

Stacktrace:

java.net.SocketException: Broken pipe
    at java.net.SocketOutputStream.socketWrite0(Native Method)
    at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
    at java.net.SocketOutputStream.write(SocketOutputStream.java:115)
    at java.io.DataOutputStream.writeBytes(DataOutputStream.java:259)
    at FR.filesRecv(Client.java:62)
    at FR.run(Client.java:79)
    at java.lang.Thread.run(Thread.java:637)

Answer 1

Some general comments:

• Yes, each client should have their own socket connection to the server.
• On the server side, there is a server socket but when a connection is accepted from a client, a new socket is created for each handler to talk to its corresponding client.
• I would fork the threads in main and then just sleep for 5 seconds and then set the runnable variables to be false. No need for the timer-task.
• You can then either exit immediately from main if you want the JVM to stop quickly or you can call join() on each of your threads to make sure they finish appropriately. You can also set thread.setDaemon(false); before the thread starts and then exit main and the JVM won’t stop until the threads finish on their own.
• You need to make sure that the runnable variable is volatile if it is going to be set from another thread.