Need help with Java program?

So i'm in an intro to java class and i'm making a Fahrenheit to Celsius converter, just for practice. I got it to work inside bluej, but when I try to run the jar file, nothing happens, but the program says that there are no syntax errors! here is my code:

import java.util.*;

public class main

{

private int farenheit;

main ()

{

farenheit = 70;

}

main ( int f )

{

farenheit = f;

}

public void setFarenheit (int differentFarenheit)

{

farenheit = differentFarenheit;

}

public void askUserForFarenheit ()

{

Scanner keyIn;

keyIn = new Scanner (System.in);

System.out.print ("Enter the temperature in Farenheit: ");

String input = keyIn.nextLine ();

int nFarenheit = Integer.parseInt (input) ;

setFarenheit (nFarenheit);

printCelcius ();

}

public void printCelcius ()

{

int f = farenheit;

double a = (f-32)*5;

double b = a/9;

String weather;

if(b > 32 )

{

weather = "It's quite hot, be sure to use sunscreen!";

}

else if (b < 22)

{

weather = "It's a little chilly, wear a sweater!";

}

else

{

weather = "It's nice and cool.";

}

System.out.println ("The temperature in celcius is " + b + " degrees.");

System.out.println ("Forecast: " + weather);

}

}