I'd like to create synchronized ArrayList in JAVA. I've used this code:
static ArrayList<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
But NetBeans yells:
incompatible types:
required: ArrayList found: List
Any help possible?
Collections.synchronizedList() returns a List, not an ArrayList. Declare the user list as such:
static List<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
List than java.util.List?Collections.synchronizedList()
returns a List. Use something like:
static List<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
Every ArrayList is a List but every List is not an ArrayList.
static List<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
Should fix the problem.
Collections.synchronizedList returns a new SynchronizedList<User> instance, cast back to List<User>. If your declaration goes
static List<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
, it will be alright.
List<User> listOfUsers = Collections.synchronizedList(new ArrayList<User>());
Worked for me
