Java - 在两个列表之间获得差异

Question

我试图在Java中找到两个列表之间的区别。我正在使用这个示例（returning difference between two lists in java）建议使用removeAll()来查找差异，但这不起作用。相反，我似乎得到了coaches和teachers的组合列表。

代码：

List<String> coaches = new ArrayList<>();
coaches.add("Josh");
coaches.add("Jake");
coaches.add("Tyler");

List<String> teachers = new ArrayList<>();
coaches.add("Josh");
coaches.add("Jake");

coaches.removeAll(teachers);

for (String name : coaches) {
    System.out.println("Name is: " + name);
}

输出：

Name is: Josh
Name is: Jake
Name is: Tyler
Name is: Josh
Name is: Jake

如何检查teachers是否缺少值Tyler，以便返回Tyler？

Answer 1

例如，在不丢失教练名单的情况下，看看谁只是一名教练而不是教师：

List<String> coaches = new ArrayList<>();
coaches.add("Josh");
coaches.add("Jake");
coaches.add("Tyler");

List<String> teachers = new ArrayList<>();
teachers.add("Josh");
teachers.add("Jake");

List<String> CoachesNotAlsoTeachers = new ArrayList<>();
CoachesNotAlsoTeachers.add(coaches);
CoachesNotAlsoTeachers.removeAll(teachers);

for (String name : CoachesNotAlsoTeachers ) {
    System.out.println("Name is: " + name);
}