Java 8 lambda create list of Strings from list of objects

You need to collect your stream into a List:

List<String> adresses = users.stream()
    .map(User::getAdress)
    .collect(Collectors.toList());

For more information on the different Collectors visit the documentation

User::getAdress is just another form of writing (User user) -> user.getAdress() which could aswell be written as user -> user.getAdress() (because the type User will be inferred by the compiler)

It is extended your idea:

List<String> tmpAdresses = users.stream().map(user ->user.getAdress())
.collect(Collectors.toList())

One more way of using lambda collectors like above answers

 List<String> tmpAdresses= users
                  .stream()
                  .collect(Collectors.mapping(User::getAddress, Collectors.toList()));

You can use this to convert Long to String:

List<String> ids = allListIDs.stream()
                             .map(listid-> String.valueOf(listid))
                             .collect(Collectors.toList());