Create an Array with random numbers

How I do create an array of size 256 with sorted random numbers in the main method? I want to create an array that randomly generates numbers between 1-256, the size would be 256 as well which means it would have 256 numbers in the array and they're sorted. My code only returns me zero?

public class Array {
    public static void main(String args[]) 
    { 
        double[] randomarray = new double[256];
        for(int i = 0; i<randomarray.length;i++)
            randomarray[i] =  Math.random();
        
        for (int i = 0; i<randomarray.length;i++)
            System.out.println(randomarray[i]);
    }
}