How to generate 6 different random numbers in java

Question

I want to generate 6 different random numbers by using Math.random and store them into an array. How can I make sure that they are different? I know I need to use for-loop t

Answer 1

That code generate numbers from 6 to 0 and save in ArrayList.

If generated number was duplicated the program generate numbers again.

If generated number is different that number is added.

Code:

private ArrayList arraylist = new ArrayList();

private Random rand = new Random();

public void insertNumber() {
    while (true) {
        int i = generateNumber();
        if(!isGenerateNumberExists(i)){
            addNumber(i);
            break;
        }
    }
}
//Generate numbers
private int generateNumber() {
    return rand.nextInt(6);
}
//Confirm if that number exists
private boolean isGenerateNumberExists(int y) {
    for (int num : arraylist) {
        if (num == y) {
            return true;
        }
    }
    return false;
}
//Add number to arrayList
private void addNumber(int x) {
    arraylist.add(x);
}