Command Line File in Java

FuelChecker.java

// this should be in your main class - more on that later
public static void main(String[] args)
{
    System.out.println(args);
    /*
        If user ran:
            java -jar FuelChecker.jar check diesal
        Output: (or similar)
            {"check", "diesal"}
    */
    
    if (args.length > 0)
    {
        if (args[0].equalsIgnoreCase("check"))
        {
            // check fuel and stuff
        }
        else
        {
            System.out.println("Invalid command! Run the JAR with no arguments to see help.");
        }
    }
    else
    {
        System.out.println("Usage: java -jar FuelChecker.jar check <fuel type>");
    }
}