Thread: Java Error Message " Public Main must be defined in own file ( Java 16777541) -How Do i resolve it

Using Viscode Creating simple Java program ( My robotic files import the libraries WPILIB for the my robotic codes , however, when i construct a simple tutorial file I run into that error on the first line " public Main must be Identified ..."
How do i create the ( Main ) file and where does it get places so that the program below can execute.
and if I'm correct
it appears that swerveDrive must somehow be resolved to the variables and it not being declared or recognized
I hope you understand the issue inspite on my poorly word issue

Program below

 public class Main {
 
 
 
 
    public static void main ( String ... args) {
        Robot swerveDrive = new Robot();   // create object instance of class
 
        swerveDrive.wheeldia = 3.0;  // inches
        swerveDrive.piniongearteeth = 12.00;
        swerveDrive.spurgearteeth = 14.00;
        swerveDrive.bevelgearteeth = 12.00;
        swerveDrive.wheelgearteeth = 44.00;
 
        swerveDrive.chassisspeedforward = 1.00; // meter per sec
        swerveDrive.Neomotorkv = 473.00;    // see Neo bushless motor spec sheet 
        swerveDrive.Neomotorfreerpm = 5676.00;   // rpm see spec sheet 
        swerveDrive.Neomotornomvoltage = 12.00;  // volts see spec sheet 
 
        System.out.println(" RobotSwerevDriveMotorVoltage is: " + swerveDrive.calculateVoltage());
 
    }
 
    static class Robot{
        double wheeldia;                      //  Define variable as integer or numericalwithdecimal
        double piniongearteeth;
        double spurgearteeth;
        double bevelgearteeth;
        double wheelgearteeth;
        double chassisspeedforward;
        double Neomotorkv;
        double Neomotorfreerpm;
        double Neomotornomvoltage;
 
        // create a method to calculate motor voltage and return value to main class 
 
        double calculateVoltage(){
            double Voltage;
 
            Voltage =   ((( chassisspeedforward * 39.37)/(wheeldia * 3.1416 )) * 60.0*((spurgearteeth/piniongearteeth)*(wheelgearteeth/bevelgearteeth))/(Neomotorkv));  
            return  Voltage ;    
        }
 
    }   
}