Java – create a unique random number

I created the following method to create a unique random number (this unique value belongs to the node of the tree):

static Random rand = new Random();
public static ArrayList<Node> go(int n) {
    ArrayList<Node> list = new ArrayList<Node>();
    ArrayList<Integer> numList = new ArrayList<Integer>();
    // TODO Auto-generated method stub
    for(int i = 1; i<=5; i++)
    {
        int number = rand.nextInt(10)+1;
        if(list.size()>0 && !check(list,number))
        {
            i--;
            continue;
        }
        numList.add(number);
        Node node = new Node();
        node.data = number;
        list.add(node);
    }
     int w  = 0;
    for (Node d : list) {
        System.out.println(w+": "+d.data);
        w++;
    }
    return list;

}
  private static boolean check(ArrayList<Node> list,int num) {
    // TODO Auto-generated method stub
    boolean b = false;
    /*if(list.size()==0)
        return true;
    */
    for (Node node : list) {
        if(node.data == num)
            b = false;
        else
            b = true;
    }
    return b;
}

But it won't create a unique number. There are still duplicate numbers in my list Like:

0: 10
1: 1 
2: 10 
3: 5 
4: 6

Solution

The problem is that if duplicate numbers are found, you won't stop the for loop in the check function If the loop continues, B can change back to true

What you should do is, for example:

private static boolean check(ArrayList<Node> list,int num) {
    for (Node node : list) {
        if(node.data == num)
            return false;
    }
    return true;
}