process gets killed on server when closing SSH session

Question

I use PuTTY to connect to my Linux (centos 8) server by SSH. then I run my java program on server by the command

java -cp /.../ app

everything is fine and the program runs continuously, but when I close my SSH session in PuTTY, my java program gets also killed. why it happens and how to prevent it?!

Answer 1

This is an expected behavior. If you want to keep running your java jar file even though you close the SSH putty session, create a shell script and try to run the java application through running the shell script.

A sample script is shown below, you can modify according to your need:

Name the script : app.sh

Sample Script Content:

#!/bin/sh

cd /home/user/    #path where your jar file is kept
java -jar app.jar

Go to the location of the script:

Give proper execute permissions to the script app.sh :
chmod 755 app.sh

Run the script as : ./app.sh

Answer 2

   nohup java -jar test.jar &

nohup is a POSIX command to ignore the HUP (hangup) signal. The HUP signal is, by convention, the way a terminal warns dependent processes of logout.

Output that would normally go to the terminal goes to a file called nohup.out if it has not already been redirected.

In short, it stands for no hang up.