Java stream - find unique elements -


i have list<person> persons = new arraylist<>(); , want list unique names. mean if there "john", "max", "john", "greg" want list "max" , "greg". there way java stream?

we can use streams , collectors.groupingby in order count how many occurrences have of each name - filter name appears more once:

    list<string> res = persons.stream()             .collect(collectors.groupingby(function.identity(), collectors.counting()))             .entryset()             .stream()             .filter(e -> e.getvalue() == 1)             .map(e -> e.getkey())             .collect(collectors.tolist());      system.out.println(res); // [max, greg]

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