How can I stop thread containing blocking operation?

Question

I'm working on a packet sniffer but I'm getting trouble about the way to stop a thread (without deprecated methods) containing a blocking method.

The concerned method is the loop() one from pcap4j library. As it is a blocking method, I put it into a thread to keep the main one working. However, in order to apply a filter to the pcap interface, I have to break the loop and restart it as the breakloop() function of the library returns an InterruptedException. So my idea was to kill the thread containing the method. But as I can't get into the library's loop causing the method to block, I'm unable to do it by checking whether the thread is interrupted or not.

Thread t = new Thread(new Runnable() {
    @Override
    public void run() {
        loop(args);
    }
});
t.start();

How can I stop it ?

EDIT : What I did was to recompile the library from its source, removing the InterruptedException from the PcapHandle class.

Answer 1

Using the Thread#getAllStackTraces you can obtain all the threads. SO Has a few other answers to this as well for getting a hold of the threads. After finding the thread you can interrupt it. The Thread.class also has some other identifiers that may help find the thread too.

Edit: Are you using kaitoy/pcap4j ? if so breakLoop() Nothing can be done about the InterruptedException, thats how the library intended for it to be broken. I would look at putting an issue in with their github if they need to implement a feature.

import java.util.Set;

class TestStuff {

    public static void main(String[] args) {
        Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
        for (Thread thread : threadSet) {
            if(thread.getName().equals("some-name")){
                thread.interrupt();
            }
        }
    }
}