Run a Java Application as a Service on Linux

Question

I have written a Java server application that runs on a standard virtual hosted Linux solution. The application runs all the time listening for socket connections and creating new handlers for them. It is a server side implementation to a client-server application.

The way I start it is by including it in the start up rc.local script of the server. However once started I do not know how to access it to stop it and if I want to install an update, so I have to restart the server in order to restart the application.

On a windows PC, for this type of application I might create a windows service and then I can stop and start it as I want. Is there anything like that on a Linux box so that if I start this application I can stop it and restart it without doing a complete restart of the server.

My application is called WebServer.exe. It is started on server startup by including it in my rc.local as such:

java -jar /var/www/vhosts/myweb.com/phpserv/WebServer.jar & 

I am a bit of a noob at Linux so any example would be appreciated with any posts. However I do have SSH, and full FTP access to the box to install any updates as well as access to a Plesk panel.

Answer 1

I wrote another simple wrapper here:

#!/bin/sh SERVICE_NAME=MyService PATH_TO_JAR=/usr/local/MyProject/MyJar.jar PID_PATH_NAME=/tmp/MyService-pid case $1 in     start)         echo "Starting $SERVICE_NAME ..."         if [ ! -f $PID_PATH_NAME ]; then             nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &             echo $! > $PID_PATH_NAME             echo "$SERVICE_NAME started ..."         else             echo "$SERVICE_NAME is already running ..."         fi     ;;     stop)         if [ -f $PID_PATH_NAME ]; then             PID=$(cat $PID_PATH_NAME);             echo "$SERVICE_NAME stoping ..."             kill $PID;             echo "$SERVICE_NAME stopped ..."             rm $PID_PATH_NAME         else             echo "$SERVICE_NAME is not running ..."         fi     ;;     restart)         if [ -f $PID_PATH_NAME ]; then             PID=$(cat $PID_PATH_NAME);             echo "$SERVICE_NAME stopping ...";             kill $PID;             echo "$SERVICE_NAME stopped ...";             rm $PID_PATH_NAME             echo "$SERVICE_NAME starting ..."             nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &             echo $! > $PID_PATH_NAME             echo "$SERVICE_NAME started ..."         else             echo "$SERVICE_NAME is not running ..."         fi     ;; esac  

You can follow a full tutorial for init.d here and for systemd (ubuntu 16+) here

If you need the output log replace the 2

nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null & 

lines for

nohup java -jar $PATH_TO_JAR >> myService.out 2>&1& 

Answer 2

A simple solution is to create a script start.sh that runs Java through nohup and then stores the PID to a file:

nohup java -jar myapplication.jar > log.txt 2> errors.txt < /dev/null & PID=$! echo $PID > pid.txt 

Then your stop script stop.sh would read the PID from the file and kill the application:

PID=$(cat pid.txt) kill $PID 

Of course I've left out some details, like checking whether the process exists and removing pid.txt if you're done.