HashSet<Integer> h =newHashSet<>();h.add(e);h.contains(e);h.remove(e);h.size();h.getOrDefault(k,default_val); h.clear();
값 출력
HashSet<Integer> set =newHashset<Integer>(Arrays.asList(1,2,3));// 전체 출력System.out.println(set);Iterator iter =set.iterator();while(iter.hasNext()) {System.out.println(iter.next());}