hmap.put("a" + String.valueOf(i), null);
            }
            System.out.println("HashMap.put:" + (System.currentTimeMillis() - start));

            start = System.currentTimeMillis();
            for (int i = 0; i < num; i++) {
                cimap.put("a" + String.valueOf(i), null);
            }
            System.out.println("CaseInsensitiveMap.put:" + (System.currentTimeMillis() - start));