java arraylist ensureCapacity not working

Question

Either I\'m doing this wrong or i\'m not understanding how this method works.

ArrayList a = new ArrayList();
a.ensureCapacity(200         


        

Answer 1

  public static void fillArrayList(ArrayList arrayList, long size) {
    for (int i = 0; i < size + 1; i++) {
      arrayList.add(i,"-1");
    }
  }

public static void main(String[] args) throws Exception {
  ArrayList a = new ArrayList(10);
  fillArrayList(a, 190);
  a.add(190,"test");
  System.out.println(a.get(190).toString());
}