Run java jar file on a server as background process

Question

I need to run a java jar in server in order to communicate between two applications. I have written two shell scripts to run it, but once I start up that script I can't shut down / terminate the process. If I press ctrl+C or close the console, the server will shut down. Could anyone help me how to modify this script to run as a normal server?

 #!/bin/sh
java -jar /web/server.jar
echo $! 
#> startupApp.pid

score 313 · Accepted Answer · answered Aug 24 '12 at 11:34

313

You can try this:

#!/bin/sh
nohup java -jar /web/server.jar &

The & symbol, switches the program to run in the background.

The nohup utility makes the command passed as an argument run in the background even after you log out.

answered Aug 24 '12 at 11:34

Anton Beloglazov

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Thanks Anton,currntly im stopping the server by killing the process id.i don't think it's best practice.is thery command to to stop the server? – Bernad Ali Aug 25 '12 at 05:01
3

Short answer: it depends on the server. Long answer: as far as I know, there is no safe way to shut down a process without the process supporting such graceful shut downs. For example, if it's a web server being terminated by an external signal, there is always a possibility that some requests will be lost. One way to solve this problem is to implement a graceful termination function in the server itself, e.g. by processing a special kind of requests. Then, the server can be terminated by sending it a request of that special kind. Otherwise, killing the process by its ID is the simple way. – Anton Beloglazov Aug 27 '12 at 00:33
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Using `nohup` should always be combined with redirecting stdout and stderr explicitly -- otherwise, you don't get control of where the logs go, and end up with an ugly `nohup.out` created in whichever directory this script happens to be invoked from. – Charles Duffy Dec 14 '18 at 16:23
@Anton when I run a script(just like your answer) with SSH EXEC runjar.sh. It started streaming the logs in my local terminal and if close my terminal my jar gets killed. How can I run a jar in the background using SSH EXEC? – AATHITH RAJENDRAN Feb 19 '20 at 06:16

score 73 · Answer 2 · edited Dec 14 '17 at 16:03

73

Systemd which now runs in the majority of distros

Step 1:

Find your user defined services mine was at /usr/lib/systemd/system/

Step 2:

Create a text file with your favorite text editor name it whatever_you_want.service

Step 3:

Put following Template to the file whatever_you_want.service

[Unit]
Description=webserver Daemon

[Service]
ExecStart=/usr/bin/java -jar /web/server.jar
User=user

[Install]
WantedBy=multi-user.target

Step 4:

Run your service
as super user

$ systemctl start whatever_you_want.service # starts the service
$ systemctl enable whatever_you_want.service # auto starts the service
$ systemctl disable whatever_you_want.service # stops autostart
$ systemctl stop whatever_you_want.service # stops the service
$ systemctl restart whatever_you_want.service # restarts the service

edited Dec 14 '17 at 16:03

answered Feb 24 '15 at 19:16

mtelesha

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This is the modern way of doing it – aardbol May 30 '19 at 18:21
4

on aws ubutnu image I had to install systemd then found the image in /etc/systemd/system/ – Robbo_UK Jun 03 '19 at 13:46
Where could I find the logs with this method? – Sajeer Babu Apr 26 '22 at 06:39
If you have created the file, but face issue like "Failed to start ---- service", then run `systemctl daemon-reload` before Step 4. https://unix.stackexchange.com/questions/364782/what-does-systemctl-daemon-reload-do – abitcode Aug 15 '22 at 19:51

score 33 · Answer 3 · edited Feb 19 '20 at 07:15

33

If you're using Ubuntu and have "Upstart" (http://upstart.ubuntu.com/) you can try this:

Create /var/init/yourservice.conf

with the following content

description "Your Java Service"  
author "You"  

start on runlevel [3]  
stop on shutdown  

expect fork  

script     
    cd /web 
    java -jar server.jar >/var/log/yourservice.log 2>&1  
    emit yourservice_running  
end script

Now you can issue the service yourservice start and service yourservice stop commands. You can tail /var/log/yourservice.log to verify that it's working.

If you just want to run your jar from the console without it hogging the console window, you can just do:

java -jar /web/server.jar > /var/log/yourservice.log 2>&1

edited Feb 19 '20 at 07:15

Serg

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answered Aug 24 '12 at 02:41

Strelok

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Is that a systemd service? This question is not tagged linux, and very few distros have systemd by default. – jordanm Aug 24 '12 at 03:15
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I will amend the question to say that this is using "upstart" which is included in ubuntu. – Strelok Aug 24 '12 at 05:34
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I believe for the last advice if you want it to run in the background and the shell got released, you should do: `java -jar /web/server.jar > /var/log/yourservice.log 2>&1 &` – Montaro May 06 '15 at 22:52
All system jobs by default live in the following directory: /etc/init/ ... By default, there is no /var/init/ directory in Ubuntu 14.04. – Michael Lafayette Sep 09 '15 at 16:30
Also, starting a service requires "sudo". sudo service yourservice start – Michael Lafayette Sep 09 '15 at 16:36

score 21 · Answer 4 · answered Jun 18 '20 at 05:29

21

Run in background and add logs to log file using the following:

nohup java -jar /web/server.jar > log.log 2>&1 &

answered Jun 18 '20 at 05:29

KayV

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Run java jar file on a server as background process

4 Answers4

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