Planet

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package planetarygravitycalculator;

/**
 *
 * @author Dan
 */
public class Planet 
{
    public final double G = 0.0000000000667;
    String planetName;
    double radius,density,mass,volume;
    
    public Planet (String name,double rad, double den)
    {
        planetName = name;
        radius = rad;
        density = den;
        this.solveMass();
    }
    
    public String getName()
    {
        return planetName;
    }
    
    public double getRadius()
    {
        return radius;
    }
    
    public double getDensity()
    {
        return density;
    }
    
    public double getMass()
    {
        return mass;
    }
    
    public double getVolume()
    {
        return volume;
    }
    
    public void setName(String newName)
    {
        planetName = newName;
    }
    
    public void setRadius(double newRad)
    {
        radius = newRad;
    }
    
    public void setDensity(double newDen)
    {
        density = newDen;
    }
    
    public void solveMass()
    {
        volume = (4.0/3.0) * Math.PI * Math.pow(radius, 3);
        mass = volume * density;
    }
    
    public double gravPull(double objMass)
    {
        double gravPull = G * ((mass * objMass) / (Math.pow(radius,2)));
        return gravPull;
    }
}

PlanetaryGravityCalculator

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package planetarygravitycalculator;



/**
 *
 * @author Dan
 */

import java.util.*;
import java.text.DecimalFormat;

public class PlanetaryGravityCalculator {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) 
    {
        Scanner scan = new Scanner(System.in);
        List<Planet> planetArray = new ArrayList<>(); 
        DecimalFormat df = new DecimalFormat("#.###");
        
        System.out.println("Welcome to the Planetary Gravity Calculator!" + "\n" + "--------------------------------------------");
        System.out.println("Enter the mass of an object: ");
        double objMass = scan.nextDouble();
        
        System.out.println("Enter how many planets you would like to calculate: ");
        int numOfPlanets = scan.nextInt();
        
        for(int i = 0; i < numOfPlanets; i++)
        {
            System.out.println("Name of planet: ");
            scan.nextLine();
            String planName = scan.nextLine();
            
            
            System.out.println("The radius of " + planName +": ");
            double planRad = scan.nextDouble();
            
            System.out.println("The average density of " + planName + ": ");
            double planDen = scan.nextDouble();
            
            Planet newPlanet = new Planet(planName,planRad,planDen);
            planetArray.add(newPlanet);
            
        }
        
        for(Planet p : planetArray)
        {
            System.out.println(p.getName() + ": " + df.format(p.gravPull(objMass)));
        }
    }
    
}