package com.baeldung.akkahttp; import java.util.ArrayList; import java.util.List; import java.util.Optional; public class UserService { private final static List users = new ArrayList<>(); static { users.add(new User(1l, "Alice")); users.add(new User(2l, "Bob")); users.add(new User(3l, "Chris")); users.add(new User(4l, "Dick")); users.add(new User(5l, "Eve")); users.add(new User(6l, "Finn")); } public Optional getUser(Long id) { return users.stream() .filter(user -> user.getId() .equals(id)) .findFirst(); } public void createUser(User user) { users.add(user); } public List getUsers(){ return users; } }