I don't mean to sidetrack, but I've deployed Java applications on Ubuntu in production since 2010 and had very little success with Upstart. I use init.d scripts and start-stop-daemon. Side bonus: it works on more distros.

Create /etc/init.d/my-java-app:

#!/bin/sh
#
# my-java-app My Java App
#
# chkconfig: - 80 05
# description: Enable My Java Application
#

### BEGIN INIT INFO
# Provides:          my-java-app
# Required-Start:    $remote_fs $network
# Required-Stop:     $remote_fs $network
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Description:       My Java Application
# Short-Description: Enable My Java Application
### END INIT INFO

DESC="my java app"
NAME=my-java-app
PIDFILE=/var/run/$NAME.pid
RUN_AS=ubuntu
WORK_DIR=/home/ubuntu/admin
DAEMON=/usr/bin/mvn
DAEMON_OPTS="spring-boot:run"

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions

do_start() {
    start-stop-daemon --start --quiet --make-pidfile --pidfile $PIDFILE \
        --background \
        --chuid $RUN_AS \
        --chdir $WORK_DIR \
        --exec $DAEMON -- $DAEMON_OPTS
}

do_stop() {
    start-stop-daemon --stop --quiet --pidfile $PIDFILE
    if [ -e $PIDFILE ]
        then rm $PIDFILE
    fi
}

case "$1" in
    start)
    echo -n "Starting $DESC: $NAME"
    do_start
    echo "."
    ;;
    stop)
    echo -n "Stopping $DESC: $NAME"
    do_stop
    echo "."
    ;;
    restart)
    echo -n "Restarting $DESC: $NAME"
    do_stop
    sleep 1
    do_start
    echo "."
    ;;
    status)
    status_of_proc -p $PIDFILE "$DAEMON" "$NAME" && exit 0 || exit $?
    ;;
    *)
    echo "usage: $NAME {start|stop|restart}"
    exit 1
    ;;
esac

Make it belong to root, make it executable, and set it up to run on startup with:

sudo chown root:root /etc/init.d/my-java-app
sudo chmod 755 /etc/init.d/my-java-app
sudo update-rc.d my-java-app defaults

To start the service you can run:

sudo service my-java-app start

To stop the service you can run:

sudo service my-java-app stop

This is based on a simplified version of the /etc/init.d/skeleton file included by Ubuntu.

The man page for start-stop-daemon is worth looking at if you want to tweak this further.b

Make sure you're on 14.04. Ubuntu 16.04 (and above) uses systemd, not Upstart.

A Upstart script is a script file placed at /etc/init/ and ending in .conf.

It requires 2 sections: one to indicate when to start, and another with the command to execute.

The easiest script to start with your sample is:

# myprogram.conf
start on filesystem
exec /usr/bin/java -jar /path_to/program

Created as root under /etc/init/myprogram.conf.

If your script requires more than one command line, use the script section instead of the exec line:

# myprogram.conf
start on filesystem
script
    /usr/bin/java -jar /path_to/program
    echo "Another command"
end script

To enable bash completion for your service, add a symlink into /etc/init.d folder:

sudo ln -s /etc/init/myprogram.conf /etc/init.d/myprogram

Then try start and stop it:

sudo service myprogram start

According the upstart cookbook, you can create pre-start/post-start and pre-stop/post-stop commands to be executed.

Additionally, I read you want to check if a process is running. Check this question and maybe use the pre-start section.

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 $PID_PATH_NAME ]; then
            PID=PID_PATH_NAME);
            echo "$SERVICE_NAME stoping ..."
            kill $PID;
            echo "$SERVICE_NAME stopped ..."
            rm $PID_PATH_NAME
        else
            echo "$SERVICE_NAME is not running ..."
        fi
    ;;
    restart)
        if [ -f $PID_PATH_NAME ]; then
            PID=PID_PATH_NAME);
            echo "$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&

Found the solution, had to set EnvironmentFile=/etc/environment and Type=forking option in my .service file then it worked fine.