I am having a trouble adding a loop or while loop to my program

I am currently in a intro java programming course at my college. My code works fine I am just trying to add a loop that will ask the user (y or n) if they would like to input another weight. The professor had posted a yesorno java program example although it is not available and still have not heard back. I emailed the lab professor who had said to add a while loop with

while( condition ) {
//do input and output of weights
//ask if they want to go again
}

although i could not get that to work either or maybe I am doing it wrong. This is what I currently have... thanks.

import java.util.*;

//I have set Planets as my main class
public class Planets 
{
	public static void main(String[] args)
	{
	
//I have declared the following variables that will be used in my program
//I used double since decimals will be used in weights.

	double weight;
	double mercury;
	double venus;
	double jupiter;
	double saturn;
	
//I have created a Scanner object and connected it to the system in object

	
	Scanner scan = new Scanner(System.in);

//I have prompted the user to input a value for the weight variable
	
	System.out.println("Please enter your Earth weight in pounds.");
	weight = scan.nextDouble();
	
	
//I have included the calculations used to determine weights on other planets

	mercury = 0.4 * weight;
	venus = 0.9 * weight;
	jupiter = 2.5 * weight;
	saturn = 1.1 * weight;
	
//This line will display the weights.

	System.out.print("Your weight on the following planets are: " + "\nMercury =" + mercury + "\nVenus = " + venus + "\nJupiter = " + jupiter + "\nSaturn =" + saturn);

//This will ask the user if they would like to enter another weight

	{String cont= "Y";
	while(cont.equals("Y"));
	
	System.out.println("Do you want to continue Y/N ?");
	cont=scan.nextLine();
	}
	}
	}