java8中stream將字符list轉換大小寫

List<String> lowCaseList = new ArrayList<>();
  lowCaseList.add("dog");
  lowCaseList.add("cat");
  lowCaseList.add("tiger");
  lowCaseList.add("lion");
   List<String> upperCaseList = lowCaseList.stream().map(String::toUpperCase).collect(Collectors.toList());
   System.out.println(upperCaseList.toString());

//結果：[DOG, CAT, TIGER, LION]