How to convert a java program to daemon with jsvc?

Question

I wrote a program and now I am expected to convert it to a daemon. Since I am a noob and dont know anything about it, can you please tell me how can I do it or can you please give me basic tutorials or readings about it ? I really want to learn how I can do it ?

Thank you all

Answer 1

Java class:

package example;  import java.util.Date; import java.util.Timer; import java.util.TimerTask; import org.apache.commons.daemon.*;  class EchoTask extends TimerTask {     @Override     public void run() {         System.out.println(new Date() + " running ...");     } }  public class Main implements Daemon {      private static Timer timer = null;      public static void main(String[] args) {         timer = new Timer();         timer.schedule(new EchoTask(), 0, 1000);     }      @Override     public void init(DaemonContext dc) throws DaemonInitException, Exception {         System.out.println("initializing ...");     }      @Override     public void start() throws Exception {         System.out.println("starting ...");         main(null);     }      @Override     public void stop() throws Exception {         System.out.println("stopping ...");         if (timer != null) {             timer.cancel();         }     }      @Override     public void destroy() {         System.out.println("done.");     }   } 

Shell start/stop script:

#!/bin/sh  # Setup variables EXEC=/usr/bin/jsvc JAVA_HOME=/usr/lib/jvm/java-6-sun CLASS_PATH="/usr/share/java/commons-daemon.jar":"/path/to/your.jar" CLASS=example.Main USER=foo PID=/tmp/example.pid LOG_OUT=/tmp/example.out LOG_ERR=/tmp/example.err  do_exec() {     $EXEC -home "$JAVA_HOME" -cp $CLASS_PATH -user $USER -outfile $LOG_OUT -errfile $LOG_ERR -pidfile $PID $1 $CLASS }  case "$1" in     start)         do_exec             ;;     stop)         do_exec "-stop"             ;;     restart)         if [ -f "$PID" ]; then             do_exec "-stop"             do_exec         else             echo "service not running, will do nothing"             exit 1         fi             ;;     *)             echo "usage: daemon {start|stop|restart}" >&2             exit 3             ;; esac 

And the effect:

$ ./service start && sleep 5 && ./service stop $ cat /tmp/example.out initializing ... starting ... Fri Oct 07 16:26:54 EEST 2011 running ... Fri Oct 07 16:26:55 EEST 2011 running ... Fri Oct 07 16:26:56 EEST 2011 running ... Fri Oct 07 16:26:57 EEST 2011 running ... Fri Oct 07 16:26:58 EEST 2011 running ... stopping ... done.