Hi this shows are to shuffle the contents of an array list so I made a little program to show it's usage hope you like it.

Code:
import java.util.ArrayList;
import java.util.Collections;

public class Main {
    public static void main(String[] args) {
        //UK lotto
        ArrayList<Integer>nums = new ArrayList<Integer>();
        //Add the numbers 1 to 59
        for(int x = 1; x<=59; x++){
            nums.add(x);
        }
        //Shuffle the nums collection.
        Collections.shuffle(nums);

        //Print the first six numbers.
        for (int x = 1; x <= 6;x++){
            System.out.print(nums.get(x) + " ");
        }
    }
}