for (int i=0;i<yourArray.length();i++)
{
     yourArray[i] = //generate random value here
}

import java.lang.*;
import java.io.*;
import java.util.Random;

public class Test
{
   private static int desiredLength;

   public static int[] intArrayOfLength(int length)
   {
      return new int[length];
   }

   public static void promptForRandomLength(PrintStream output = System.out) throws IOException
   {
      output.print("Please input a random length: ");
   }

   public static void readRandomLength(InputStream input = System.in) throws IOException
   {
      BufferedReader in = new BufferedReader(new InputStreamReader(input));
      desiredLength = Integer.parseInt(in.readLine());
   }

   public static int[] intArrayOfDesiredLength()
   {
      return intArrayOfLength(desiredLength);
   }

   public static void populateIntArrayWithRandomValues(int[] arr)
   {
      Random randNum = new Random(System.currentTimeMillis());
      for (int i = 0; i <arr.length; i++)
          arr[i] = randNum.nextInt();
   }

   public static void main(String[] args)
   {
      int[] myArray;
      promptForRandomLength();
      readRandomLength();
      myArray = intArrayOfDesiredLength();
      populateIntArrayWithRandomValues(myArray);
   }
}