JAVA:Two runnable Threads questions, computer science homework help

" Write a Java program that demonstrates two Runnable classes, each of which contains a Thread.Objects in one class generate random rolls of a pair of dice and display them. The number of rolls can be set in a constructor.Objects in the other class display random Strings selected from an array. The number of Strings selected and displayed can be set in a constructor.Show how the behavior of the threads can interleave.Show how to synchronize them using join." I know how to do a dice and string generator. But i am having trouble create two runnable classes of threads for this problem. Heres my code: package testing;import java.util.Random;import java.math.*;public class dice{ public int sides; public dice(int sides) // DIY howm many side of dice you want { // use: diec diceA = new dice(7) = now means you want 7 sides dice this.sides = sides; } public int roll() { int roll = 0; Random generator = new Random(); roll = Math.abs(generator.nextInt()%sides+1);// this will give us a number from -6 to +6 so need abs function return roll;// give a number from -7 to +7 }}----------this is string generator-------package stringgenerator;import java.util.Random;import java.util.Scanner;public class StringGenerator{ public static void main(String[] args) { int length; Scanner input = new Scanner(System.in); System.out.println("How many friends name that you are gonna enter:"); length = input.nextInt(); String[] names = new String[length]; for (int counter = 0;counter < length; counter ++) //read from user { System.out.println("Enter the name of the friend:" + (counter+1)); names[counter] = input.next(); } input.close(); //stop System.out.println("your friends are"); // display for (int counter =0;counter < length; counter++) { System.out.println(names[counter]); } System.out.println("Random name!:"+names[ new Random().nextInt(names.length)]); //generate random name from the list }}