HashMapping a cubic volume

Question

I am trying to map a zero indexed value to a multidimensional array list using the map function so that I can assign data to specific values within the arraylist without having to constantly request that I Dex location. The code I have written is not compiling for some reason.

Could so eone please check it their side please and also criticise where required?

`

package main.java.javatestfiles;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * #####CORRECTED#####
 * 
 * The purpose of the class is to map a cubic calculation to
 * a multidimensional arraylist as the partials iterate over
 * the cubic sum of n in the key to value mappings.
 * 
 * Help from : https://www.javatpoint.com/java-map
 * 
 * @author devel
 */

public class Cubic_Mapping_2 {
    
    public static void main(String[] args) {
        
        int j, k, l, i;
        
        double n = 4.0;
        
        double v = Math.pow(n, 3.0);
        
        ArrayList<ArrayList<ArrayList<Integer>>> c = new ArrayList<>();
        
        Map map = new HashMap();
        
        for (j = 0; j <= v-1; j++) {
            for (k = 0; k <= n; k++) {
                for(l = 0; l <= n; l++) {
                    for (i = 0; i <= n; i++) {
                        map.put(c.get(k).get(l).get(i), j);
                    }
                }
            }
        }
        
        Set set = map.entrySet(); //Converting to Set so that we can traverse
        
        Iterator itr = set.iterator();
        
        while(itr.hasNext()){
            
            //Converting to Map.Entry so that we can get key and value 
        
            Map.Entry entry = (Map.Entry) itr.next();  
            System.out.println(entry.getKey() + " " + entry.getValue());  
        }
    }
}

`

Thank you, look forward to hearing from you.

R

Tried swapping the key and value variables around, <int, arraylist> and tried calling c variable as an output to check content, however that will not work because there is no content it is a mapping schema.

There does not seem to be any error message on compile in VSCode however in eclipse just a generic exception for 0 index.

################################################################

I wrote a new solution -

`

package javatestfiles;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;

/**
 * The purpose of the class is to map a cubic calculation to
 * a multidimensional ArrayList as the partials iterate over
 * the cubic sum of n in the key to value mappings.
 * 
 * Help from : https://www.javatpoint.com/java-map
 *             https://www.baeldung.com/java-multi-dimensional-arraylist
 *             https://www.w3schools.com/java/java_hashmap.asp
 *             https://www.geeksforgeeks.org/java-util-hashmap-in-java-with-examples/
 *              
 * @author devel
 */

public class Cubic_Mapping_3 {
    
    static Map<Integer, Object> map = new HashMap<>();
    static ArrayList<ArrayList<ArrayList<Object>>> c;
    
    /**
     * Populate an ArrayList with n indices cubed.
     * 
     * @param n
     * @return Three dimensional ArrayList c
     */
    public static ArrayList<ArrayList<ArrayList<Object>>> three_d_list(int n) {
        
        int i, j;
        int x_axis = n;
        int y_axis = n;
        int z_axis = n;
        
        ArrayList<ArrayList<ArrayList<Object>>> c = new ArrayList<>(x_axis);
        
        for (i = 0; i <= x_axis; i++) {
            c.add(new ArrayList<ArrayList<Object>>(z_axis));
            
            for (j = 0; j < z_axis; j++) {
                c.get(i).add(new ArrayList<Object>(y_axis));
            }
        }
        
        return c;
    }
    
    /**
     * Randomly populate the mapped volumetrics with Neurons
     * @param neuron
     * @param qty - Quantity of neurons
     * @param v - Received autonomously from mapping()
     */
    public static void populate(Object neuron, int qty, double v) {
        
        Random rand = new Random();
        
        int i;
        
            for (i = 0; i <= qty; i++) {
                map.put(rand.nextInt((int) v), neuron);
            }
    }
    
    /**
     * Maps the cubic index length to the ArrayList c and calls the populate()
     * autonomously to populate the list and the mapping with the Neurons
     * 
     * @param neuron - An Objectified ArrayList comprising the AI and areas / proximities
     * @param qty - The quantity of Neurons to deploy randomly in your mapped volumetrics
     * @param n - The index to be used to calculate the cubic size of the volume
     */
    public static void mapping(ArrayList<Object> neuron, int qty, int n) {
        int j, k, l, i;
        
        double v = Math.pow(n, 3);
        
        ArrayList<ArrayList<ArrayList<Object>>> c = three_d_list(n);
        
        for (j = 0; j < n; j++) {
            for (k = 0; k < n; k++) {
                for(l = 0; l < n; l++) {
                    c.get(j).get(k).add(l);
                    for (i = 0; i < v; i++) {
                        map.put(i, c.get(j).get(k).get(l));
                    }
                }
            }
        }
        
        populate(neuron, qty, v);
    }
    
    /**
     * Clear the data in memory store after use.
     */
    public static void clearall() {
        map.clear();
        c.clear();
    }
    
    public static Map<Integer, Object> main(String[] args) {
        
        mapping(null, 0, 0); //Entry point, the autonomy does the rest.
        
        return map;

    }
}

`