Set<String> set1 = Stream.of("Kotlin", "Java", "Rust", "Python", "C++").collect(Collectors.toSet()); Set<String> set2 = Stream.of("Kotlin", "Java", "Rust", "Ruby", "C#").collect(Collectors.toSet()); Set<String> expectedOnlyInSet1 = Set.of("Python", "C++"); set1.removeAll(set2); //removeAll method can be used to calculate the difference between sets