How to initialize List object in Java?

If you check the API for List you’ll notice it says:
Interface List

Being an interface means it cannot be instantiated (no new List() is possible).
If you check that link, you’ll find some classes that implement List:

All Known Implementing Classes:
AbstractList, AbstractSequentialList, ArrayList, AttributeList, CopyOnWriteArrayList, LinkedList, RoleList, RoleUnresolvedList, Stack, Vector

Those can be instantiated. Use their links to know more about them, I.E: to know which fits better your needs.
The 3 most commonly used ones probably are:
List supplierNames1 = new ArrayList();
List supplierNames2 = new LinkedList();
List supplierNames3 = new Vector();

Bonus:
You can also instantiate it with values, in an easier way, using the Arrays class, as follows:
List supplierNames = Arrays.asList(“sup1”, “sup2”, “sup3”);
System.out.println(supplierNames.get(1));

But note you are not allowed to add more elements to that list, as it’s fixed-size.

Can’t instantiate an interface but there are few implementations:
JDK2
List list = Arrays.asList(“one”, “two”, “three”);

JDK7
//diamond operator
List list = new ArrayList<>();
list.add(“one”);
list.add(“two”);
list.add(“three”);

JDK8
List list = Stream.of(“one”, “two”, “three”).collect(Collectors.toList());

JDK9
// creates immutable lists, so you can’t modify such list
List immutableList = List.of(“one”, “two”, “three”);

// if we want mutable list we can copy content of immutable list
// to mutable one for instance via copy-constructor (which creates shallow copy)
List mutableList = new ArrayList<>(List.of(“one”, “two”, “three”));

Plus there are lots of other ways supplied by other libraries like Guava.
List list = Lists.newArrayList(“one”, “two”, “three”);