Joint use skills of joiner.on and stream().Map

List<String> test=new ArrayList<>();
test.add(" I ");
test.add(" you ");
String result = Joiner.on("&").join(test);
List<String> collect = test.stream().map(item -> "\"" + item + "\"").collect(Collectors.toList());
String join = Joiner.on("&").join(collect);