I am writing this little Lottery application. Now the plan is, to count how often each number has been drawn during each iteration of the Lottery, and store this somewhere. My guess is that I would need to use a HashMap, that has 6 keys and increments the value by one everytime the respective keys number is drawn. But how would I accomplish this? My code so far:

public void numberCreator()
{
    // creating and initializing a Random generator
   Random rand = new Random();
   // A HashMap to store the numbers picked. 
   HashMap hashMap = new HashMap();
   // A TreeMap to sort the numbers picked.
   TreeMap treeMap = new TreeMap();

    // creating an ArrayList which will store the pool of availbale Numbers
    List<Integer>numPool = new ArrayList<Integer>();

    for (int i=1; i<50; i++){
    // add the available Numbers to the pool
    numPool.add(i); 
    hashMap.put(nums[i], 0);
    }

    // array to store the lotto numbers
    int [] nums = new int [6];

    for (int i =0; i < nums.length; i++){
    int numPoolIndex = rand.nextInt(numPool.size());
    nums[i] = numPool.get(numPoolIndex);

    // check how often a number has been called and store the new amount in the Map
    int counter =  hashMap.get

    numPool.remove(numPoolIndex);
    }

    System.out.println(Arrays.toString(nums));

    }

Maybe someone can tell me if I have the right idea, or even how I would implement the map properly?