Why a "java.net.SocketException: Broken pipe" will occur?

Question

I wrote a simple socket programme, it works fine, but my friend use a port scanning tool, when it scan to the port I am using, it cash with "java.net.SocketException: Broken pipe" error, what's happen? and how to solve it?

providerSocket = new ServerSocket(portNum);
connection = providerSocket.accept();
if (connection.getOutputStream() != null) {
    //this line crash!!!
    out = new ObjectOutputStream(connection.getOutputStream());
    out.flush();

}

Detail Error from console:

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:136)
    at java.io.ObjectOutputStream$BlockDataOutputStream.drain(ObjectOutputStream.java:1847)
    at java.io.ObjectOutputStream$BlockDataOutputStream.setBlockDataMode(ObjectOutputStream.java:1756)
    at java.io.ObjectOutputStream.<init>(ObjectOutputStream.java:230)

`connection.getOutputStream()` doesn't return null. The test is pointless. — user207421, Mar 02 '12 at 04:58

score 8 · Accepted Answer · answered Mar 02 '12 at 04:15

Some port scanners work by starting to open a connection and then immediately terminating it. Your server is not programmed to deal with a connection failure because you did not code for that possibility. You will need to use a try/catch to trap that condition and recover. Also, you should probably be handing off the connection to a separate thread for processing, so your main program can continue to receive new connections (and sending them to threads to be handled).

score 2 · Answer 2 · answered Mar 02 '12 at 11:40

2

I think this happens when remote end closed the connection;

answered Mar 02 '12 at 11:40

Santhosh Kumar Tekuri

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TheSecond · Answer 3 · 2016-11-09T14:30:33.770

0

The reason of your problem may be here:

JavaDoc:

The maximum queue length for incoming connection indications (a request to connect) is set to 50. If a connection indication arrives when the queue is full, the connection is refused.

And you should increase "backlog" parameter of your ServerSocket, for example

int backlogSize = 50 ;
providerSocket = new ServerSocket(portNum, backlogSize);

edited Nov 09 '16 at 14:30

answered Nov 13 '15 at 07:39

TheSecond

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8

score 0 · Answer 4 · answered Mar 23 '12 at 01:03

Either used throws clause with SocketException and IOException or put try catch finally as my friend suggested above.In finally dont forget to close all streams that you are using.And also check your port number at both client and server side programs.Hopw this will help.

Why a "java.net.SocketException: Broken pipe" will occur?

4 Answers4

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