Running Java Program from Command Line Linux - Stack Overflow
How to run Java application on startup of Ubuntu Linux - Stack Overflow
How to start a .jar file using Java on Ubuntu
Run a Java Application as a Service on Linux - Stack Overflow
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If your Main class is in a package called FileManagement, then try:
java -cp . FileManagement.Main
in the parent folder of the FileManagement folder.
If your Main class is not in a package (the default package) then cd to the FileManagement folder and try:
java -cp . Main
More info about the CLASSPATH and how the JRE find classes:
- How Classes are Found
- Setting the class path (Solaris/Linux)
- http://en.wikipedia.org/wiki/Classpath_(Java)
Guys let's understand the syntax of it.
If class file is present in the Current Dir.
java -cp . fileName
If class file is present within the Dir. Go to the Parent Dir and enter below cmd.
java -cp . dir1.dir2.dir3.fileName
If there is a dependency on external jars then,
java -cp .:./jarName1:./jarName2 fileName
Hope this helps.
Ideally you should create a service wrapper for your java application and then make this service run on startup example here.
Use
sudo update-rc.d mytestserv defaults to run your service wrapper on startup on Ubuntu
So two things you'll need to do:
First create a small shell script to start your java program from a terminal. As you have packaged as a jar have a look at this, specifically the JAR Files as Applications section.
This may be sufficient: (although you'll want to use the full path to Java)
#!/bin/bash
java -jar path_to_jar_file
You should be able to run your script and successfully start your program.
Once you've got it starting from a script you can use standard linux tools to start the script. Either putting it in /etc/rc.local, or as you're using Ubuntu, use update-rc.d to start it on boot. See here for a very simple example of using update-rc.d
Hope this helps,
Will
Ok, i just spent way too much time on trying to figure this out. Hopefully this will help someone who's searching for a solution to this same problem. I have Lubuntu 24.04, this instruction is for this system but will probably work for other Ubuntu OS versions.
To start a .jar file using Java, right-click the file in a file manager (in my case, PCManFM-Qt),
click "Open With...",
choose the "Custom command" tab,
in the "Command to execute" field, enter "java -jar" (only the bold text, without the quotation marks),
Also you can choose the option "Set selected application as default for this file type" or something like that so every .jar file gets opened by Java. But that's if you want your system to do that.
Also it helps to enter the Application Name in the appropriate field so that it's not just empty when you select the "Open with..." option in your file manager.
Then click "OK".
I'm not very knowledgeable on Linux in general, but this worked for me and hopefully this will save someone some time and they won't have to figure it out like i had to.
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 $PATH_TO_JAR >> myService.out 2>&1&
A simple solution is to create a script start.sh that runs Java through nohup and then stores the PID to a file:
nohup java -jar myapplication.jar > log.txt 2> errors.txt < /dev/null &
PID=$!
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.