A TreeSet or TreeMap that allow duplicates

You can use a PriorityQueue.

PriorityQueue<Integer> pQueue = new PriorityQueue<Integer>(); 

PriorityQueue(): Creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering.

This is a link to doc: https://docs.oracle.com/javase/8/docs/api/java/util/PriorityQueue.html

I need all the fundCode with highest fundValue

If that's the only reason why you want to sort I would recommend not to sort at all. Sorting comes mostly with a complexity of O(n log(n)). Finding the maximum has only a complexity of O(n) and is implemented in a simple iteration over your list:

List<Fund> maxFunds = new ArrayList<Fund>();
int max = 0;
for (Fund fund : funds) {
    if (fund.getFundValue() > max) {
        maxFunds.clear();
        max = fund.getFundValue();

    }
    if (fund.getFundValue() == max) {
        maxFunds.add(fund);

    }
}

You can avoid that code by using a third level library like Guava. See: How to get max() element from List in Guava

you can sort a List using Collections.sort.

given your Fund:

List<Fund> sortMe = new ArrayList(...);
Collections.sort(sortMe, new Comparator<Fund>() {
  @Override
  public int compare(Fund left, Fund right) {
    return left.fundValue.compareTo(right.fundValue);
  }
});
// sortMe is now sorted