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Why would my spring boot application will shut down automatically？

update：
I have followed spring boot deployment for Installation as an init.d Service (System V). I start my application successfully.But, after one day.My application closed again......Is there any ways to help me ?
I hava one spring boot application which names my.jar. I put it into my ubuntu server(20.04) and use the command of nohup java -jar my.jar &.In the first few hours, my application is in good condition.But,after one or two days,it will shut down automatically.
I have seen the log of my application which don't recorded any error and saved the last correct log before exiting
The current situation is my application is very simple and have only a small number of visits.
According to my guess,it is seems that ubuntu kill my process for inactivity?
My scripts are as follow,
stop.sh:
#!/bin/bash
PID=$(ps -ef | grep centre-0.0.1-SNAPSHOT.jar | grep -v grep | awk '{ print $2 }')
if [ -z "$PID" ]
then
echo Application is already stopped
else
echo kill $PID
kill $PID
fi
run.sh:
#!/bin/bash
echo stop application
source stop.sh
echo start application
source start.sh
start.sh:
#!/bin/bash
nohup java -jar centre-0.0.1-SNAPSHOT.jar &
I need my application will run all the time.
Is there any ways to resolve the issue?

nohup is more suited for running processes that are expected to end after a while. For example running a lengthy batch script.
As of why it is killed, there may be a number of reasons: memory leak, server security policy .... The server probably decided your program wasn't behaving correctly. Logs of the server, like dmesg or /var/log/ contents may have some clues about it.
What you said about your app receiving visits feels like it is more a service rather than a script.
You may want to
daemonize your program
. this will make your program tied to the server availability.
Here is an explanation of the differences between nohup and daemons.
Also check this link at baeldung for help on setting up the daemon

After I check the memory usage, so I realized that my spring boot have used a lot of memory abnormally.
I solved it in the following way:
I updated my start.sh with the command of "nohup java -Xms100m -Xmx300m -jar ./target/centre-0.0.1-SNAPSHOT.jar &"
But, I did not figure out why did my spring boot application use a lot of memory?
Is there anyone can explain this phenomenon?

sudo: effective uid is not 0 when running under tomcat service

I have a small java web app (grails), deployed under tomcat 8, from which I would like to execute a script on the local server using sudo. On a regular debian/ubuntu server all I have to do is use visudo to allow the tomcat user to execute sudo without a password on that particular script, and everything works as expected. When I tried installing the same war file on the raspberry pi (model 3b+, raspbian 10 - buster), booting from an SD card, the execution of the script always fails with the error "sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges'.
In an effort to track down this issue I have written another small executable jar that performs the same function (i.e. attempts to launch the script using sudo). This test program works as expected when logged in interactively (bash) as both the 'pi' and 'tomcat8' users (I had to set a shell for the tomcat8 user to order to get an interactive login). I then used strace to try and diagnose the issue. All I could glean from that is that getuid() is returning 111 (tomcat8) when trying to launch sudo when running under the tomcat8 service, but will return 0 when running in bash.
I have also written a small c program that simply calls getuid() and prints the result. If I run it under the tomcat8 user interactively (i.e. sudo su tomcat8), it prints '111' when I run it without sudo, and '0' when I run it with sudo. When I try and launch this program from the web-app (using process builder) I get '111' when the command is run without sudo, but I get the 'effective uid is not 0 ...' error when the command is prefixed with sudo.
I have checked mount, and there are a number of mounts with the 'nosuid' attribute, but not the root '/' directory where /usr/bin is located, and /usr/bin/sudo looks to have the correct permissions:
pi#raspberrypi:~/dev $ ls -l /usr/bin/sudo
-rwsr-xr-x 1 root root 147560 Jan 13 2019 /usr/bin/sudo
In desperation I have tried a couple of other things to just see what effect they might have:
* Added the tomcat8 user to adm, sudo and other groups
* Attempted to remount the other mounts without the nosuid attribute, although I couldn't remount about 6 or so because the mounts where in use.
Neither of these appeared to have any effect.
So it seems to me that the tomcat8 user can use sudo when in bash, but not when running as a daemon. Can anyone give me some ideas as to what is going on here? Is there anyway to diagnose or trace how an effective uid is determined by the os?
Other things that may be significant:
I installed both openjdk-8-jdk and tomcat8 via apt, and even though raspbian uses systemd, tomcat8 is launched via an init.d script. Not sure if this is causing uid issues.
If it is the SD card having some mounts with the nosuid attribute causing the problem, why doesn't it fail when running interactively?

It turns out it was an issue with the way the daemon is started, probably due to changes in the way Debian 10 starts daemon processes. I removed the tomcat init.d script, and replaced it with a systemd unit file, and included the following properties:
[Service]
...
NoNewPrivileges=false
AmbientCapabilities=CAP_SETGID CAP_SETUID
SecureBits=keep-caps
This allows the daemon to actually call setUid(0) successfully.

Centos java custom service

I have a script.sh that set some environment variable and start a java server.
#!/bin/bash
export JAVA_HOME="/opt/java"
export ....
nohup $JAVA_HOME/bin/java "$MEMORY_JAVA_OPS" -classpath "$MY_CLASSPATH" $MAIN_CLASS &
I would like to transform this script (now is launched by /etc/rc.d/rc.local) in a service.
I tried many examples found online and over StackOverflow.
I created myservice.service file using many templates found online... No one work!
one example is:
[Unit]
Description=MyService Java Process Restart Upstart Script
After=auditd.service systemd-user-sessions.service time-sync.target
[Service]
User=root
TimeoutStartSec=0
Type=simple
KillMode=process
#export JAVA_HOME=/opt/java/jdk-9
#export PATH=$PATH:$JAVA_HOME/bin
WorkingDirectory=/tmp/myworkdir
ExecStart=/path/to/myscript.sh
[Install]
WantedBy=multi-user.target
With some configurations, the service starts but the status command says that it is dead (while it is actually running). With others it does not start. With none it stops with the command stop ....
I tried Type=Simple, forking, oneshot... always some problem.
I would simply that after boot or when user launch systemctl start myservice, service start, and if after some time crash will be started again. And if I will run systemclt stop myservice it stops and not need to kill the process.

Firstly it need to be said, that concept "service" greatly differs in Linux/Unix and Windows environment. From your question seems to me you are looking for Unix solution.
In unix you typically register some statup and stop script/command. The startup script just runs your java application via java -jar app.jar. This application does business logic & also opens listening on some SHUTDOWN port.
The stop script/command just invokes another (or the same with different cmd parameters) java application which does nothing else just sending STOP command to original application's SHUTDOWN port.
You can look in more detail for example on tomcat startup/stop scripts - they are doing exactly this.
For windows is better to use some wrappers like WinRun4J or whatever else. Of course you can have one multiplatform maven archetype for "universal multiplatform" service like we do.
EDITED:
If you are still unsure how to configure it on Linux, read https://linuxconfig.org/how-to-create-systemd-service-unit-in-linux
ExecStart will be the startup java -jar app.jar and ExecStop will be the stopping command java -jar app-stopper.jar

Bash script to start java if not running, with other java programs running

i usually use this bash script to check if my java application is running and start it again if not. I use crontab to check it
#!/bin/bash
if [ "$(pidof java)" ]
then
# process was found
echo "application running"
else
# process not found
cd /home/assist/emanager
setsid java -jar emanager-1.0.0.jar </dev/zero &>/dev/null &
fi
Now the problem is that there are other java applications running on the server, so the script does not start my app because the if condition is true. Is there a way to check if a specific java application is running?
Thanks

Your question is very similar to this one:
Start a Java application using Bat file if not already started
The main difference is you are asking for bash while the other one is in Windows. Hence replace jcmd with jps, the rest is still applicable.

How can I find out the pid of a running equinox instance, is there a pid file?

How can I find out the pid of a running equinox instance, is there a pid file somewhere or is it configurable where it places a pid file?
UPDATE: to make it clear, I have a bunch of instances running, and they are configured roughly the same, so any user only looking for equinox will not know which instance is which

Just execute the following command from CLI:
ps aux | grep equinox
[EDIT]
Does equinox bind to some port?
If so, for multiple instances you can recognize the one you are interested in basis on port to which it is bound:
sudo netstat -npa |grep equinox

No, Equinox does not create a PID file or report its PID.
You could write a bundle that does this for you, but be aware that there is no standard way for a Java program to retrieve its PID (because some target operating systems don't even have the concept of "PID"). See this post for some ideas.

$ pidof equinox
From the man page:
PIDOF(8) Linux System Administrator's Manual PIDOF(8)
NAME
pidof -- find the process ID of a running program.
SYNOPSIS
pidof [-s] [-c] [-x] [-o omitpid] [-o omitpid..] program [program..]
DESCRIPTION
Pidof finds the process id's (pids) of the named programs. It prints
those id's on the standard output. This program is on some systems used
in run-level change scripts, especially when the system has a System-V
like rc structure. In that case these scripts are located in
/etc/rc?.d, where ? is the runlevel. If the system has a start-stop-
daemon (8) program that should be used instead.
OPTIONS
-s Single shot - this instructs the program to only return one pid.
-c Only return process ids that are running with the same root
directory. This option is ignored for non-root users, as they
will be unable to check the current root directory of processes
they do not own.
-x Scripts too - this causes the program to also return process
id's of shells running the named scripts.
-o omitpid
Tells pidof to omit processes with that process id. The special
pid %PPID can be used to name the parent process of the pidof
program, in other words the calling shell or shell script.
EXIT STATUS
0 At least one program was found with the requested name.
1 No program was found with the requested name.