Generating an array of random numbers without duplicates [duplicate]

Answer 1

As far as I understand what you are doing, a better way would/could be:

List myList = new ArrayList();
for ( int i = 0; i < expectedNumberOfUniques; i++){
  Integer a = generateRandom();
  while ( myList.contains(a)){
    a = generateRandom();
  }
  myList.add(a);
}

A few remarks, though: the more elements in myList, the less efficiënt it might be less efficiënt.

But: as soon as you limit it to 'no duplicates allowed', we are no longer talking about 'random' numbers.