Question

I am creating a TFTP server and keep it running using a infinite loop. When i try to send a kill signal

/bin/kill -s SIGINT <pid>

I want Java process to close TFTP server and exit.

class TFTP {
public void startTFTP(String str, String str1){
    try {
        //Start TFTP server
            // Both of below are not working.
            Runtime.getRuntime().addShutdownHook(new Thread(){
                @Override
                public void run(){
                    //Shutdown tftp server
                    System.out.println("Exiting");
                    System.exit(0);
                }
            });

            SignalHandler handler = new SignalHandler () {
                public void handle(Signal signal) {
                    System.exit(0);
                }
            };
            Signal.handle(new Signal("INT"), handler);
            Signal.handle(new Signal("TERM"), handler);

            while(true){
            // Infinite loop to keep process running.
            }
        }
    } catch (Exception e) {

    }
}
public static void main(String args[]){
        TFTP tftp = new TFTP();
        tftp.startTFTP(args[0],args[1]);
}

}

I kill the process from a script and calling

/bin/kill -s SIGINT <pid>

doesn’t kill the java process for some reason. I thought SIGINT is handled as part of

Signal.handle(new Signal("INT"), handler);

What am i missing here?

Regards
Dheeraj Joshi

Answer 1

I think you need to sent ‘SIGTERM’ (‘kill’ w/o ‘-s’ parameter) for shutdown hook to work.