Writing a script to run a Java program

1. Open a text editor and create a new file.
2. Copy and paste the below script into the file.

#!/bin/bash

# Set the Java home directory
JAVA_HOME=/path/to/java/home

# Set the classpath and main class name
CLASSPATH=/path/to/your/application.jar
MAIN_CLASS=com.example.YourMainClass

# Check if the program is already running
if pgrep -f "$MAIN_CLASS" >/dev/null; then
    echo "Stopping the running instance of the program..."
    pkill -f "$MAIN_CLASS"
    sleep 5 # Wait for the program to stop gracefully
fi

# Run the Java program
echo "Starting the program..."
$JAVA_HOME/bin/java -cp $CLASSPATH $MAIN_CLASS

3. Replace /path/to/java/home with the actual path to your Java installation directory.
4. Replace /path/to/your/application.jar with the actual path to your compiled Java application’s JAR file.
5. Replace com.example.YourMainClass with the fully qualified name of your application’s main class.
6. Save the file with a “.sh” extension, such as “run.sh”.
7. Open a terminal and navigate to the directory where you saved the script.
8. Make the script executable by running the command: chmod +x run.sh
9. Run the script by executing the command: ./run.sh

The script first checks if the program is already running using pgrep. If a running instance is found, it stops the program using pkill. After ensuring that the previous instance has stopped, it starts a new instance of the Java program using the specified Java home directory, classpath, and main class. Adjust the script as per your specific application’s requirements.