// Declare and Initialize the Collection Set<Integer> intSet = new HashSet<Integer>(); // Add Elements intSet.add(1); intSet.add(2); intSet.add(3); intSet.add(4); // Use the stream and collectors to get List out of Set List li = intSet.stream().collect(Collectors.toList()); System.out.println(li); // Prints [1, 2, 3, 4]