Running Java Applications as Services on Linux

To ensure continuous operation and easy management of Java server applications on Linux, it is often desirable to run them as services. This guide explores a solution that addresses these requirements.

The Need for Services

In a virtual hosted Linux environment, Java applications may be started manually or via scripts like rc.local, but this approach lacks the flexibility and control required for seamless maintenance. To manage applications independent of server restarts, consider running them as services.

Creating a Service Script

To create a service script, follow these steps:

#!/bin/sh
SERVICE_NAME=your_service_name
PATH_TO_JAR=full_path_to_jar_file
PID_PATH_NAME=/tmp/your_service_name-pid
case $1 in
    start)
        echo "Starting $SERVICE_NAME ..."

        # Check if service is already running
        if [ ! -f $PID_PATH_NAME ]; then

            # Execute Java command in the background (daemonize)
            nohup java -jar $PATH_TO_JAR > /tmp/service_name.log 2>&1 &

            # Store PID to track process
            echo $! > $PID_PATH_NAME
            echo "$SERVICE_NAME started ..."
        else
            echo "$SERVICE_NAME is already running ..."
        fi
    ;;
    stop)
        # Check if PID file exists to ensure service is running
        if [ -f $PID_PATH_NAME ]; then
            PID=$(cat $PID_PATH_NAME)
            echo "$SERVICE_NAME stopping ..."

            # Kill process
            kill $PID
            echo "$SERVICE_NAME stopped ..."

            # Remove PID file
            rm $PID_PATH_NAME
        else
            echo "$SERVICE_NAME is not running ..."
        fi
    ;;
    restart)
        # Stop service
        if [ -f $PID_PATH_NAME ]; then
            PID=$(cat $PID_PATH_NAME)
            echo "$SERVICE_NAME stopping ..."
            kill $PID
            echo "$SERVICE_NAME stopped ..."
            rm $PID_PATH_NAME
        else
            echo "$SERVICE_NAME is not running ..."
        fi

        # Start service
        echo "$SERVICE_NAME starting ..."
        nohup java -jar $PATH_TO_JAR > /tmp/service_name.log 2>&1 &
        echo $! > $PID_PATH_NAME
        echo "$SERVICE_NAME started ..."
    ;;
esac 

Installation

1. Save the above script as a file with a ".sh" extension (e.g., "myservice.sh").
2. Make the script executable: chmod x myservice.sh.
3. Copy the script to the appropriate directory (e.g., /etc/init.d or /lib/systemd/system).

Usage

To manage the service, use the following commands:

• Start: /etc/init.d/myservice start or systemctl start myservice
• Stop: /etc/init.d/myservice stop or systemctl stop myservice
• Restart: /etc/init.d/myservice restart or systemctl restart myservice

Conclusion

This guide provides a comprehensive solution for running Java applications as services on Linux, offering the control and flexibility required for efficient management and maintenance.