Interrupt a thread in DatagramSocket.receive

Question

I'm building an application that listens on both TCP and UDP, and I've run into some trouble with my shutdown mechanism. When I call Thread.interrupt() on each of the listening threads, the TCP thread is interrupted from listening, whereas the UDP listener isn't. To be specific, the TCP thread uses ServerSocket.accept(), which simply returns (without actually connecting). Whereas the UDP thread uses DatagramSocket.receive(), and doesn't exit that method.

Is this an issue in my JRE, my OS, or should I just switch to (Datagram)Socket.close()?

UPDATE: I've found an analysis of the problem. It confirms that the behavior is not consistent.

Answer 1

A common idiom for interrupting network IO is to close the channel. That would be a good bet if you need to effectively interrupt it while its waiting on sending or receiving.

public class InterruptableUDPThread extends Thread{     private final DatagramSocket socket;     public InterruptableUDPThread(DatagramSocket socket){       this.socket = socket;    }    @Override    public void interrupt(){      super.interrupt();        this.socket.close();    } } 

Answer 2

As far as I know, close() is the proper way to interrupt a blocked socket. Interrupting and keeping open something that may have already done a partial read or write makes things unnecessarily complex. It's easier to only have to deal with a "success" or "give up" result.