countUniqueInList.java

public static <T> Map<T, Integer> getCounts(List<T> list) {
    Map<T, Integer> counts = new HashMap<T, Integer>();
    for(T item : list) {
        if(!counts.containsKey(item)) {
            counts.put(item, 0);
        }
        counts.put(item, counts.get(item) + 1);
    }
    return counts;
}