int boxCount[i]  =  (int) (Math.random()*6) + 1;

This line of code looks like you are trying to create an array or something.

You want to create the array boxCount BEFORE your for loop:

int boxCount[] = new int[100];

Then you can do this in your loop:

boxCount[i]  =  (int) (Math.random()*6) + 1;

It should be like

 ar1[i] = (int)(Math.random() * 100);

When you cast, cast type should be in brackets e.g. (cast type)value

You need to add logic to assign random values to double[] array using randomFill method.

Change

 public static double[] list(){
    anArray = new double[10];   
    return anArray;
 }

To

 public static double[] list() {
    anArray = new double[10];
    for(int i=0;i<anArray.length;i++)
    {
        anArray[i] = randomFill();
    }
    return anArray;
}

Then you can call methods, including list() and print() in main method to generate random double values and print the double[] array in console.

 public static void main(String args[]) {

list();
print();
 }

One result is as follows:

-2.89783865E8 
1.605018025E9 
-1.55668528E9 
-1.589135498E9 
-6.33159518E8 
-1.038278095E9 
-4.2632203E8 
1.310182951E9 
1.350639892E9 
6.7543543E7 

You can use the Random generator to generate a random index and return the element at that index:

//initialization
Random generator = new Random();
int randomIndex = generator.nextInt(myArray.length);
return myArray[randomIndex];